# folium
## English
### Etymology

From Latin folium (“leaf”). Doublet of foil and folio, distantly also with phyllo and phyllon.

### Pronunciation

* Audio (US):(file)

### Noun

folium (countable and uncountable, plural foliums or folia)
* (rare) A leaf.
** 1994, Tamás Fazekas, Béla Selmeczi, Pál Stefanovits, Magnesium in Biological Systems, page 281:278.0 common walnut-tree folium
** 2013, Susana Garcia de Arriba, Belal Naser, and Klaus-Ulrich Nolte, “Risk Assessment of Free Hydroquinone Derived from Arctostaphylos Uva-ursi folium Herbal Preparations”, in International Journal of Toxicology, volume 32, number 6:In conclusion, under the recommended use conditions Uva-ursi folium is a safe therapeutic option for treating lower urinary tract infections.
** 2016, Gustavo Politis, Nukak: Ethnoarchaeology of an Amazonian People, pages 7-15:The fire is stoked by blowing through a hollow cane made from the folium of the tucum palm.
* A leaf (2 pages) of a codex or manuscript.
** 1979, California Studies in Classical Antiquity - Volume 12, page 225:But Barwick and Robinson both investigated V, and inform us that V leaves almost a full folium vacant (only the first two lines of folium 227 being occupied by the text before the lacuna).
** 2001, Alan David Crown, Samaritan Scribes and Manuscripts, page 74:However, the columns of the uncial manuscripts should be seen as elements in a text block on the folium for they betray the cannons in vogue for writing the codex as it is possible to verify from a continuing tradition.
** 2003, Mahārājā Mānasiṃha Pustaka Prakāśa, David Edwin Pingree, A Descriptive Catalogue of the Sanskrit Astronomical Manuscripts Preserved at the Maharja Man Singh II Museum in Jaipur, India, page 125:On f. 1 the second scribe has written an anukramajikā (on the left is noted the folium number, on the right the adhyāya number):
** 2013, Nathan Sidoli, Glen Van Brummelen, From Alexandria, Through Baghdad, page 220:Thus the order of the folia originating in the Archimedean codex is known, but the order of the text does not show where one quire began and how many folia were bound into one quire.
* A document that acts as the legal record of a transaction.
** 1834 November 8, “Tallies”, in The Mirror of Literature, Amusement, and Instruction, number 690, page 326:Giving tallies was a royal mode of contracting debts by our early sovereigns, as Exchequer bills have been the means of raising loans in our times: indeed, the Exchequer bill was the counter-tally, or folium of the tally; and the court of Exchequer has existed in its late order since the days of Edward I., by whom it was regulated and reduced from the institution of the ancient Norman Exchequer, introduced here by William the Conqueror.
** (especially real estate) A certificate of title.
*** 1872, Registration of Title (Australian Colonies), page 6464:There may nevertheless be a separate certificate and folium for any derived estate deed.
*** 1872, Edward Jenkins, Discussions on Colonial Questions, page 59:When this occurs, the existing declaration of title or conveyance is cancelled, the existing folium of the record closed, a fresh declaration of title issued to the new proprietor, and a new folium opened in the record book, upon which are carried forward the memorials of all lesser estates, interests, and charges affecting the land, and continuing current at the time of recording the change of ownership of the freehold.
*** 1899, Proceedings of the Eighteenth Annual Session of the Texas Bar Association, page 24:The duplicate certificates are bound into a register and each forms a distinct folium of the register of one or more pages, for recording all dealings affecting the land, whether fee simple, lesser estate, mortgage, charge or interest, whether subsisting at the time the certificate is issued or subsequently created.
*** 1961, John Baalman, The Singapore Torrens Systems, page 65:Where land is the subject of frequent dealings, a stage is reached at which the folium of the land-register becomes incapable of holding futher endorsements.
* A thin sheet or plate of a foliated rock or mineral.
** 1846, Charles Darwin, Geological Observations on South America:By varying the supposed angle of the tilt, our previously inclined folia can be thrown into any angle between 26 degrees, which is the least possible angle, and 90 degrees; but if a small inclination be thus given to them, their point of dip will depart far from the north, and therefore not accord with the actual position of the folia of mica-schist on our granitic range.
** 1887, Charles Callaway, “A Preliminary Inquiry into the Genesis of the Crystalline Schists of the Mavern Hills”, in The Quarterly Journal of the Geological Society of London, page 529:The folia of quartz are longer, thinner, and more uniform in thickness.
** 1949, Edson S. Bastin, “The Gold Log Mine, Talladega County, Alabama”, in Bulletin of the United States Geological Survey, page 160:The contacts between ore and schist are as a rule extremely sharp, in places cutting across the folia of the schist, and sharp fragments of schist are here and there inclosed by ore.
* (anatomy) A lobe on a branching structure.
** 1906, John Arthur Thomson, William Dawson Henderson, James J. Simpson, An Account of the Alcyonarians Collected by the Royal Indian Marine Survey Ship Investigator in the Indian Ocean, page 230:The folia of these project considerably beyond the level of the soft cœnenchyma, and produce a very rugose appearance.
** 1988, Gábor Inke, The Protolobar Structure of the Human Kidney, page 375:The folium represents the second largest gross morphologic unit of the human kidney in those protolobes that are undivided and the third largest unit in subdivided protolobes in which the lobes are present.
** 2018, Marcelle K. Boudaugher-Fadel, Evolution and Geological Significance of Larger Benthic Foraminifera, page 433:The folia are short, free or fused at the tips to form a ring of imperforate umbilical piles.
** A leaf-like protrusion or lobule on one of the vermes of the cerebellum.
*** 1904, The Journal of Anatomy and Physiology, Normal and Pathological, page 465:The vermis portion of lobule C$_3$ remains small, and still consists of only one folium.
*** 1905, Daniel John Cunningham, Text-book of anatomy, page 514:These diverge so sharptly from each other that they almost form a right angle with the parent stem, and they run parallel to the long axis of the folium, threading their way between the branches of the various dendritic planes of the cells of Purkinje and entering into contact association with them.
*** 1918, Henry Gray, Robert Howden, Anatomy, Descriptive and Applied, page 781:The cells are flattened in a direction transverse to the long axis of the folium, and thus appear broad in sections carried across the folium, and fusiform in sections parallel to the long axis of the folium.
*** 1956, Wilfrid Edward Le Gros Clark, Archibald Durward, The Anatomy of the Nervous System, page 913:A cerebellara folium is composed of a central core of white matter covered with a layer of grey matter.
* (geometry) A curve of the third order, consisting of two infinite branches having a common asymptote. The curve has a double point, and a leaf-shaped loop.
** 1881, Henry M. Jeffery, “On Bicircular Quartics, with a Triple and Double Focus, and Three Single Foci, all of them Collinear.”, in Proceedings of the London Mathematical Society, volume 12, page 22:These circular cubics are Newton's defective hyperbolae, with a diameter, species 39, 41, 45; the ampullate cubic represents the folium of the unipartite quartic, and the ampaniform the bipartite quartic.
** 2011, Laura Ruetsche, Interpreting Quantum Theories, page 222:I have argued that the real threat the Unruh effect poses to fundamental partical interpretation lies in its suggestion that physically reasonable states outrun the folium of any single irreducible Fock space representation.
* (uncountable) Synonym of turnsole (“purple dye”)
** 1847, Theophilus (Presbyter), An essay upon various arts, tr., with notes, by R. Hendrie, page 58:Folium is thus described . "Folium is used for dying cloths and is a red colour, and another kind is purple, and another is blue.
** 1860, William Robert Tymms, M. Digby Wyatt, The Art of Illuminating as Practised in Europe from the Earliest Times, page 68:The "folium" of the Greek illuminators was procured from plants growing abudantly near Athens, while that of the Hiberno-Saxon Scribes was obtained from the "norma" or "gorma" of the Celts.
** 1981, Joachim E. Gaehde, The Painters of the Carolingian Bible Manuscript of San Paolo Fuori Le Mura in Rome, page 80:There is a strong probability that the violets of the san Paolo Bible were roduced by a mixture of folium and album.
** 1995, John Block Friedman, Northern English Books, page 90:The major initial on folio 12, however, contains a folium-colored ground, and green ink appears prominently.
* (zoology) A symmetric pattern on the abdomen of some spiders.
** 1885, James Henry Emerton, New England Spiders of the Family Therididae - Volume 6, page 298:The folium of silvatica has a row of oblique black markings along the edge on each side, while in angulata it is evenly notched.
** 1995, A. T. Barrion, J. A. Litsinger, Riceland Spiders of South and Southeast Asia, page 631:Abdomen subovate to subtriangular, longer than wide, dorsum with an inverted Christmas tree-like folium of brown and chalk-white bands, cardiac area brown, serving as Christmas tree base.
** 2017, Lawrence Bee, Geoff Oxford, Helen Smith, Britain's Spiders: A Field Guide, page 371:The abdomen usually has a flattened anterior edge and its pattern, if present, lacks the folium of Xysticus and is much less structured.

#### Derived terms

* bifolium
* folium of Descartes

## Latin
### Etymology

Traditionally derived from Proto-Indo-European *bʰolh₃yom (“leaf”), from *bʰleh₃- (“blossom, flower”), and thus an exact cognate of Ancient Greek φῠ́λλον (phŭ́llon).
An alternative theory, favored by Driessen and De Vaan, derives the word from Proto-Indo-European *dʰolyom, from *dʰelh₁- (“be green”), whence Middle Irish duille, Welsh dail, Ancient Greek θάλλω (thállō, “to bloom”), Old Armenian դալար (dalar, “green, fresh”), Albanian dal (“to exit, go out”).

### Pronunciation

* (Classical Latin) IPA: /ˈfo.li.um/, [ˈfɔlʲiʊ̃ˑ]
* (modern Italianate Ecclesiastical) IPA: /ˈfo.li.um/, [ˈfɔːlium]

### Noun

folium n (genitive foliī or folī); second declension
* a leaf (including a conifer's needle)
** 79 CE, Pliny the Elder, “chapter 16”, in Naturalis Historia, book 16:Ex his pinus atque pinaster folium habent capillamenti modo praetenue longumque et mucrone aculeatum.Of these, the pine and wild pine have a leaf [that is] very thin and long, in the manner of hair, and tipped with a sharp point.
* a petal
* (Late Latin) a sheet or leaf of paper
* (figuratively) trifle, thing of no consequence

#### Declension

Second-declension noun (neuter).
$^1$Found in older Latin (until the Augustan Age).

#### Derived terms

* acrifolius
* aquifolius
* exfoliāris
* folia
* foliāceus
* foliamen (Medieval Latin)
* foliātum
* foliātus
* foliōsus
* latifolius

#### Related terms

* foliātilis
* foliātūra

#### Descendants

* Aragonese: fuella
* Aromanian: foalji
* Asturian: fueya; → foliu
* Catalan: full, fulla; → foli
* Dalmatian: fualja
* → English: folio, folium (learned)
* Franco-Provençal: fôlye
* Old French: fueille (see there for further descendants)
* → French: feuille
* Istro-Romanian: foľe
* Italian: foglia, foglio
* Neapolitan: fuoglio
* Norman: fielle
* Northern Italo-Romance:
** Friulian: fuee
** Piedmontese: feuj
** Romagnol: fój (Central Romagnol)
** Romansch: fegl, figl, föglia
** Venetan: fogia, foja, fogio, fojo
* Occitan: fuèlh, fuèlha, huelha
* Portuguese: folho; → fólio
* Romanian: foaie; → foliu
* Sardinian: fógiu, fògia, folla, foza
* Sicilian: fogghia, fogghiu
* Spanish: hoja; → folio
* Walloon: foye

### References

* “fŏlĭum”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
* “folium”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
* "folium", in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
* fŏlĭum in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette, page 678/1.
* “folium” on page 719/3 of the Oxford Latin Dictionary (1st ed., 1968–82)
* Niermeyer, Jan Frederik (1976) “folium”, in Mediae Latinitatis Lexicon Minus, Leiden, Boston: E. J. Brill, page 439/2
* ↑ De Vaan, Michiel (2008) “folium”, in Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, page 230

## Romanian
### Etymology

Borrowed from Latin folium.

### Noun

folium n (plural foliumuri)
* (geometry) folium

#### Declension
### References

* folium in Academia Română, Micul dicționar academic, ediția a II-a, Bucharest: Univers Enciclopedic, 2010. →ISBN