arboretum
A place where many varieties of tree are grown for research, educational, and ornamental purposes.

arboretums
plural of arboretum

arborways
plural of arborway

arcadianism
An ideal rustic or pastoral state.

arccosh
Alternative form of arcosh (“the inverse hyperbolic cosine function”).

arccoth
Alternative form of arcoth (“the area hyberbolic cotangent function, i.e., the inverse hyperbolic cotangent function.”).

archaeoplankton
Any marine plankton of the kingdom Archaea

archaeplastidan
Any autotrophic eukaryote of the kingdom Archaeplastida

archaeplastidans
plural of archaeplastidan

archbasilica
A supreme basilica. The title is currently held only by the Archbasilica of St. John Lateran, the cathedral of Rome.

archbasilicas
plural of archbasilica

archbishophood
The rank of archbishop; the state of being an archbishop.

archdeaneries
plural of archdeanery

archdeanery
The headquarters, or jurisdiction of an archdean.

archduchies
plural of archduchy

archduchy
The territory (principality) of an archduke.

archdukedom
The territory or dignity of an archduke or archduchess; an archduchy.

archdukedoms
plural of archdukedom

archenmity
Supreme enmity; the state of archenemies.

archeparch
The archbishop of an archeparchy.

archeparchs
plural of archeparch

archiater
The chief, or highest-ranked physician of a prince, city or country, such as the Holy Roman Empire

archiaters
plural of archiater

archididascalos
A school principal.

archimandrite
The superior of a large monastery, or group of monasteries, in the Orthodox Church.
An honorary title sometimes given to a monastic priest.

archimandrites
plural of archimandrite

archisynagogue
The head of a synagogue.

archisynagogues
plural of archisynagogue

archmarshal
The grand marshal of the Holy Roman Empire.

archmarshals
plural of archmarshal

archpresbyteries
plural of archpresbytery

archpresbytery
The absolute dominion of presbytery.

archprimate
The chief primate of a Christian church.

archprimates
plural of archprimate

archway
A passageway covered by an arch, particularly one made of masonry.
A doorway with a semilunar-shaped top.

archways
plural of archway

arcosh
The area hyperbolic cosine function, i.e., the inverse hyperbolic cosine function.

arcosolia
plural of arcosolium

arcosolium
A tomb in an arched recess in a wall.

arcoth
The area hyperbolic cotangent function, i.e., the inverse hyperbolic cotangent function.

arcsch
The area hyperbolic cosecant function, i.e., the inverse hyperbolic cosecant function.

arcsech
Alternative form of arsech (“the inverse hyberbolic secant function”).

arcsinh
Alternative form of arsinh (“the inverse hyperbolic sine function”)

arctanh
Alternative form of artanh (“the inverse hyberbolic tangent function”)

ardhamandapa
A half-open entrance porch on a Hindu temple.

areaorama
A tunnel book.

areaway
An outdoor passage offering access to a basement.

areaways
plural of areaway

arenaful
as much as an arena would hold.

arenafuls
plural of arenaful

arenasful
plural of arenaful

arenicolite
A wormhole or other burrowing tunnel preserved in sandstone or another rock.

arenicolites
plural of arenicolite

areoid
The analogue of the geoid for the planet Mars; the Martian geoid. The gravitational and rotational equipotential surface for Mars. The surface that provides the datum line (the equivalent for sea level) for Mars.

areoids
plural of areoid

argentei
plural of argenteus

argenteus
A silver coin, minted in the Roman Empire between 294 and 310, weighing approximately 3 scruples.

aridification
The long-term process by which a region becomes more arid

aridland
The land of an arid environment.

aridlands
plural of aridland

arkstorm
A very severe rainstorm lasting for many days, fed by an atmospheric river, causing massive flooding.

arkstorms
plural of arkstorm

armarian
Synonym of armarius (“medieval monastery librarian”).

armarians
plural of armarian

armarius
The librarian in a medieval monastery, who kept, repaired and catalogued its manuscripts and books.

arminacean
A sea slug of the suborder Arminacea.

arminaceans
plural of arminacean

arminid
Any of the sea slugs in the family Arminidae.

arminids
plural of arminid

armshouse
Bloodshed, violence.

arrentation
A letting or renting, especially a licence to enclose land in a forest with a low hedge and ditch, under a yearly rent.

arrentations
plural of arrentation

arsech
The area hyperbolic secant function, i.e., the inverse hyperbolic secant function.

arsinh
The area hyperbolic sine function, i.e., the inverse hyperbolic sine function.

artanh
The area hyperbolic tangent function; i.e., the inverse hyperbolic tangent function (or hyperbolic arctangent)

arthamandapa
Alternative spelling of ardhamandapa.

arthroseries
Alternative form of arthro-series.

artophoria
plural of artophorion

artophorion
The tabernacle on the high altar in an Eastern Orthodox church

artspace
An art gallery that offers art-related activities and events.

artspaces
plural of artspace

ascidiacean
Any of the class Ascidiacea of sea squirts.

ascidiaceans
plural of ascidiacean

ashdump
A place where ashes are dumped.

ashdumps
plural of ashdump

ashfield
A field that is covered in ash.

ashfields
plural of ashfield

ashflow
The flow of ash from a volcano.

ashflows
plural of ashflow

ashram
A secluded religious hermitage inhabited by gurus, or the population of such a hermitage.

ashrams
plural of ashram

asiarch
Alternative form of Asiarch.

asiarchs
plural of asiarch

aspidochirote
Synonym of aspidochirotid.

aspidochirotes
plural of aspidochirote

aspidochirotid
Any sea cucumber of the order Aspidochirotida

aspidochirotids
plural of aspidochirotid

aspidodiadematid
Any of the sea urchins in the family Aspidodiadematidae.

aspidodiadematids
plural of aspidodiadematid

assignat
A banknote used during the French Revolution, on the security of state land.

assignats
plural of assignat

asterinid
Any in the family Asterinidae of sea stars.

asterinids
plural of asterinid

astika
A philosophical school or individual accepting certain tenets fundamental to Hinduism, by various definitions:
A philosophical school or individual accepting certain tenets fundamental to Hinduism, by various definitions:
A philosophical school or individual accepting certain tenets fundamental to Hinduism, by various definitions:

astogeny
Any morphological change in colonial zooids as the colony grows

astrobleme
A pit-like structure created by an impacting meteoroid, asteroid or comet.

astroblemes
plural of astrobleme

astrophorin
Any sea sponge of the suborder Astrophorina

astrophorins
plural of astrophorin

astrotechnology
Space technology.
Synonym of xenotechnology.
The technology of astronomy

astrotourist
A space tourist.

astrotourists
plural of astrotourist

astyonym
Any proper name by which a city is known.

atabegate
The realm administered by an atabeg.
The office of atabeg, in his role as tutor to a crown prince or as warlord.

atabegates
plural of atabegate

atam
plural of utum.

atelier
A studio or workshop, especially for an artist, designer, or fashion house.

ateliers
plural of atelier

athenaeum
Alternative form of Athenaeum: a temple primarily dedicated to Athena or her Roman equivalent Minerva.
An association or institution for the advancement of learning, particularly in science or literature.
The reading room or library of such an association; (by extension) any reading room or library.
A literary or scientific periodical, especially one similar to the London Athenaeum.

athenaeums
plural of athenaeum

athenarian
Any sea anemone of the infraorder Athenaria

athenarians
plural of athenarian

athenea
plural of atheneum

atheneum
Alternative form of athenaeum.

atheneums
plural of atheneum

atheocracy
An atheist or irreligious state.