# tropism
## English
### Etymology

From -tropism (suffix meaning ‘growth towards; movement, turning’) (possibly based on geotropism and heliotropism), from Latin tropus + English -ism (suffix forming nouns of action, process, or result). Tropus is derived from Ancient Greek τρόπος (trópos, “a turn; a manner, style, way; figure of speech, trope; etc.”), from τρέπω (trépō, “to turn; to divert; to rotate or change orientation”) (from Proto-Indo-European *trep- (“to turn”)) + -ος (-os, suffix forming nouns of result or abstract nouns of action).
Sense 1 (“turning of an organism or part of an organism towards or away from a stimulus”) is modelled after German Tropismus.

### Pronunciation

* (Received Pronunciation) IPA: /ˈtɹəʊpɪz(ə)m/
* (General American) IPA: /ˈtɹoʊˌpɪzəm/
* Audio (Southern England):(file)
* Hyphenation: trop‧i‧sm

### Noun

tropism (countable and uncountable, plural tropisms)
* (uncountable, biology) The turning of an organism (chiefly a plant) or part of an organism either towards or away from a stimulus; (countable) an instance of this.
** 1900 January, Walter E[ugene] Garrey, “The Effects of Ions upon the Aggregation of Flagellated Infusoria: A Dissertation Submitted to the Faculties of the Graduate Schools of Arts, Literature, and Science, in Candidacy for the Degree of Doctor of Philosophy (Department of Physiology)”, in American Journal of Physiology, volume 3, number 6, Bethesda, Md.: American Physiological Society, →DOI, →ISSN, →OCLC, page 313:Orientation and tropism are synonymous expressions; that gatherings [of Paramecium] take place is a consequence of the orientation, and therefore throws no light whatever upon the tropisms. (Gatherings, however, are not always indicative of a tropism, i.e., of an orientation, but may be due to kinesis […]
** 1972 November, “Samples of the Student Proposals as Submitted by Students”, in Skylab Student Project: Information for Teachers (including Classroom Activities) (NASA EP; 106), Washington, D.C.: National Aeronautics and Space Administration, →OCLC, page 17, column 1:Phototropic orientation of an embryo plant in zero gravity […] On earth, a germinated seedling can be placed in any position and the radicle will invariably turn the embryo plant "downward" and the hypocotle "upward". This is because positive root tropism toward gravity and negative stem tropism away from gravity. In the absence of gravity, will the plumules and the stem of the embryo plant reacting positively to phototropism guide the entire plant including the root system for its directional orientation?
** 2021, Michael Friedman, Karin Krauthausen, Barbara Mazzolai, quoting Barbara Mazzolai, “Interview with Barbara Mazzolai: Plants, Plantoids, and Active Materials”, in Peter Fratzl, Michael Friedman, Karin Krauthausen, Wolfgang Schäffner, editors, Active Materials, Berlin; Boston, Mass.: Walter De Gruyter, →DOI, →ISBN, page 139:Tropism means that the roots or branches move by turning towards or turning away from environmental stimuli. We have implemented this behavior in the roots of the plantoid [i.e., a robot or synthetic organism designed to act like a plant], integrating sensors and using an adaptive material for growing.
* (countable, by extension, chiefly virology) A capability or tendency for a pathogen (chiefly a virus) to infect a type of cell, tissue, organ, or host organism.
    host tropism    tissue tropism
** 1964, J. J. Holland, “Viruses in Animals and in Cell Culture”, in Joan Taylor, editor, Microbial Behaviour, ‘in Vivo’ and ‘in Vitro’: Fourteenth Symposium of the Society for General Microbiology Held at the Royal Institution, London, April 1964, Cambridge, Cambridgeshire: Cambridge University Press for the Society for General Microbiology, →OCLC, page 271:Studies similar to those describe above for cells cultivated in vitro were performed using homogenates of tissues and organs from humans and rhesus monkeys to investigate tissue tropisms in susceptible species […] McLaren (personal communication) found an excellent correlation between poliovirus tissue tropisms and presence or absence of receptor activity in human and rhesus tissues and organs.
** 1977, D. J. Evans, “Picornavirus Receptors, Tropism and Pathogenesis”, in M. A. McCrae, J. R. Saunders, C. J. Smyth, N. D. Stow, editors, Molecular Aspects of Host–pathogen Interactions: Fifty-fifth Symposium of the Society for General Microbiology Held at Heriot-Watt University, Edinburgh, March 1997, Cambridge, Cambridgeshire: Cambridge University Press for the Society for General Microbiology, →ISBN, page 23:Virus tropism can be defined at two levels: host tropism being the range of host species that a virus can productively infect, and tissue tropism reflecting the particular tissues or organs within the host that are the site(s) of virus replication. […] The primary determinant of virus tropism is the presence on the cell surface of a suitable receptor which the virus can utilize to gain entry to the cell.
** 1989 January 4, Susan P. Spring, Ann Scluederberg, William P. Allen, Jack Gruber, “Commentary: Pathogenic Diversity of Epstein-Barr Virus”, in Robert E. Wittes, editor, Journal of the National Cancer Institute, volume 81, number 1, Bethesda, Md.: National Cancer Institute, National Institutes of Health, Public Health Service, Department of Health & Human Services, →ISSN, →OCLC, page 19, column 1:HBLV [human B-cell lymphotropic virus] has a broad range of cell tropisms, and it infects B cells, T cells, megakaryocytes, and glioblastoma cells.
** 1994, William C. Russell, Mária Benkö, “Animal Viruses”, in Robert G[ordon] Webster, Allan Granoff, editors, Encyclopedia of Virology, volume 1, London; San Diego, Calif.: Academic Press, →ISBN, pages 16–17:A very wide spectrum of tissue tropism among the animal adenoviruses is evident, e.g. porcine adenovirus type 3 shows a tropism for columnar epithelial cells whereas bovine adenoviruses prefer capillary endothelial cells; however, it is not clear how far tissue tropism relates to pathogenesis and disease.
** 1999, Frederick A. Murphy, E. Paul J. Gibbs, Marian C. Horzinek, Michael J. Studdert, “Mechanisms of Infection and Viral Spread through the Body”, in Veterinary Virology, 3rd edition, San Diego, Calif.; London: Academic Press, →ISBN, part I (Principles of Virology), page 97, column 1:The capacity of a virus to selectively infect cells in particular organs is referred to as tropism […]. Viral tropism depends on viral and host factors.
** 2011, Christon J. Hurst, “The Relationship between Humans, Their Viruses, and Prions”, in Christon J. Hurst, editor, Studies in Viral Ecology: Animal Host Systems, volume 2, Hoboken, N.J.: Wiley-Blackwell, John Wiley & Sons, →ISBN, section II (Viruses of Macroscopic Animals), page 361, column 1:Orthoreovirus has primary tropisms associated with its acquisition and transmission as an upper respiratory infection and those include the facial sinuses, lungs, pharynx, and tonsils, presumably its tropism towards the intestines represents a secondary tropism (assuming that fecal-oral transmission does not also represent a primary route of disease spread, in which case the intestines would have to be considered a primary tropism), […]
* (countable, figurative) Of a person: an instinctive predilection or tendency; also (generally), a liking, a preference.
** 1911, Isaac A[mada] Cornelison, “Tropism”, in The Natural History of Religious Feeling: A Question of Miracles in the Soul, New York, N.Y.; London: G[eorge] P[almer] Putnam’s Sons, The Knickerbocker Press, →OCLC, part I (The Natural Causes of Religious Feeling), page 10:It is reasonable to suppose that tropism will be less conspicuous in animals which are endowed with intelligence than in others; but well-marked tropisms are still to be found among the higher animals. Gregarious animals have a positive tropism toward the members of their own flock; the dog has a negative tropism toward his own kind and a positive tropism toward mankind.

#### Usage notes

* Sense 1 is generally distinguished from taxis which is used to refer to organisms such as animals and bacteria which are able to move from place to place and so can relocate towards or away from stimuli. Tropism is used to refer to organisms such as fungi and plants which are not motile, and simply turn towards or away from stimuli.
* Sense 1 should also be distinguished from kinesis or nastic movement (an individual movement being called a nasty), which is non-directional or even random movement in response to stimuli.
* Not to be confused with trophism.

#### Derived terms

* tropistic

#### Related terms

* tropic
* -tropy (and its deratives)

#### Translations
### References

* 1 2 “tropism, n.”, in OED Online ⁠, Oxford: Oxford University Press, July 2023.
* ↑ “tropism, n.”, in Dictionary.com Unabridged, Dictionary.com, LLC, 1995–present, reproduced from Stuart Berg Flexner, editor in chief, Random House Unabridged Dictionary, 2nd edition, New York, N.Y.: Random House, 1993, →ISBN.
* ↑ Douglas Harper (2001–2025) “tropism”, in Online Etymology Dictionary.
* ↑ “-tropism, comb. form”, in OED Online ⁠, Oxford: Oxford University Press, July 2023.
* ↑ “-tropism, comb. form”, in Collins English Dictionary.

### Further reading

* host tropism on Wikipedia.Wikipedia
* tissue tropism on Wikipedia.Wikipedia
* tropism on Wikipedia.Wikipedia

### Anagrams

* imports, primost, promist

## Romanian
### Etymology

Borrowed from French tropisme.

### Noun

tropism n (plural tropisme)
* tropism