13-letter words containing i, a, t, r
- arctic circle — The Arctic Circle is an imaginary line drawn around the northern part of the world at approximately 66° North.
- arctic willow — a low-growing shrub, Salix arctica, of the tundra
- arcticologist — a person who specializes in arcticology.
- argentiferous — containing or bearing silver
- argentine ant — a small brown ant, Iridomyrmex humilis, introduced into the southern U.S. from South America: a household and fruit pest.
- argumentation — Argumentation is the process of arguing in an organized or logical way, for example in philosophy.
- argumentative — Someone who is argumentative is always ready to disagree or start quarrelling with other people.
- aridification — the process by which a humid region becomes increasingly dry, as by climatic change or human interference with the ecology.
- aridity index — a number indicating how much more precipitation could be lost by evapotranspiration if it were available than is actually lost at a given location.
- aristocracies — Plural form of aristocracy.
- aristocratism — the principles of aristocrats
- aristolochene — (organic compound) A bicyclic sesquiterpene produced by certain fungi.
- arithmetician — a person skilled in arithmetic
- arithmophobia — the fear of numbers
- arkansas city — a city in S Kansas.
- arm wrestling — a contest in which two people sit facing each other each with one elbow resting on a table, clasp hands, and each tries to force the other's arm flat onto the table while keeping his own elbow touching the table
- armamentarium — the items that comprise the material and equipment used by a physician in his professional practice
- armistice day — the anniversary of the signing of the armistice that ended World War I, on Nov 11, 1918, now kept on Remembrance Sunday
- armor-plating — The armor-plating on a vehicle or building is the hard metal covering that is intended to protect it from gunfire and other missiles.
- armstand dive — a dive starting from a handstand at the end of a springboard or a platform with the diver's back to the water.
- aromatization — the conversion of aliphatic or alicyclic compounds to aromatic hydrocarbons.
- arretine ware — a red-glazed terracotta pottery produced in Tuscany from 100 b.c. to a.d. 100 and widely traded.
- arseniuretted — combined with arsenic so as to form an arsenide.
- artaxerxes ii — died ?358 bc, king of Persia (?404–?358). He defeated his brother Cyrus the Younger at Cunaxa (401)
- arterializing — Present participle of arterialize.
- arteriography — the X-ray examination of an artery or arterial system after injection of a contrast medium into the bloodstream
- arteriovenous — of, relating to, or affecting an artery and a vein
- artesian well — well sunk through impermeable strata receiving water from an area at a higher altitude than that of the well
- arthritically — in an arthritic manner
- arthroconidia — Plural form of arthroconidium.
- arthroscopies — Plural form of arthroscopy.
- articulations — Plural form of articulation.
- artificiality — artificial quality.
- artificialize — to render artificial
- aryepiglottic — pertaining to or connecting the arytenoid cartilage and the epiglottis.
- ascertainable — to find out definitely; learn with certainty or assurance; determine: to ascertain the facts.
- ascertainably — In a way that can be ascertained.
- ascertainment — to find out definitely; learn with certainty or assurance; determine: to ascertain the facts.
- aspartic acid — nonessential amino acid that is a component of proteins and acts as a neurotransmitter
- aspirationals — Plural form of aspirational.
- assassinators — Plural form of assassinator.
- assault rifle — a firearm that is capable of firing multiple rounds in a very short period
- assertability — The quality of being assertable.
- assertiveness — confidently aggressive or self-assured; positive: aggressive; dogmatic: He is too assertive as a salesman.
- assortatively — In an assortative way.
- assortativity — (mathematics) The extent to which nodes of a graph link to others of the same degree.
- assyriologist — A person who studies ancient Assyria.
- astereognosis — inability to recognize objects by touch
- asteroid belt — the concentrations of asteroids that move around the sun mainly between the orbits of Mars and Jupiter
- astrodynamics — the study of the motion of natural and artificial bodies in space