13-letter words containing a, t, o, r
- 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
- asthenosphere — a thin semifluid layer of the earth (100–200 km thick), below the outer rigid lithosphere, forming part of the mantle and thought to be able to flow vertically and horizontally, enabling sections of lithosphere to subside, rise, and undergo lateral movement
- astrodynamics — the study of the motion of natural and artificial bodies in space
- astronautical — of or relating to astronautics or astronauts.
- astroparticle — (astrophysics) A subatomic particle of cosmic origin.
- astrophysical — Of or pertaining to astrophysics.
- aten asteroid — one of a small group of asteroids whose orbits cross that of the earth and whose semimajor axes are smaller than that of the earth.
- athenagoras i — (Aristocles Spyrou) 1886–1972, Archbishop Ecumenical of Constantinople and Ecumenical Patriarch of the Greek Orthodox Church 1948–72.
- atherogenesis — (medicine) The formation of atheromas, especially on the walls of the arteries.
- atmospherical — pertaining to, existing in, or consisting of the atmosphere: atmospheric vapors.
- atomic energy — nuclear energy
- atomic number — the number of protons in the nucleus of an atom of an element
- atomic theory — any theory in which matter is regarded as consisting of atoms, esp that proposed by John Dalton postulating that elements are composed of atoms that can combine in definite proportions to form compounds
- atrabilarious — Characterized by melancholy or gloom.
- atroceruleous — a deep blue-black color.
- atrociousness — The state of being atrocious.
- attested form — a linguistic form that can be shown to be in use or in written records
- attributional — of or relating to the act of attributing
- auctioneering — Present participle of auctioneer.
- austroasiatic — a family of languages spoken in SE Asia and the landsaround the Bay of Bengal and consisting principally of Vietnamese, Khmer, Mon, Khasi, Nicobarese, and the Munda languages.
- autapomorphic — (biology) Describing any characteristic that has evolved in only a single species (or other taxon).
- auteur theory — the theory that creative directors are the major force in film-making
- authenticator — a person or thing that authenticates.
- authorisation — Alternative spelling of authorization.
- authoritarian — If you describe a person or an organization as authoritarian, you are critical of them controlling everything rather than letting people decide things for themselves.
- authoritative — Someone or something that is authoritative gives an impression of power and importance and is likely to be obeyed.
- authorization — an authorizing or being authorized
- auto-destruct — self-destruct.
- auto-injector — An auto-injector is a hypodermic syringe that you can use to inject yourself with a liquid.
- autobiography — Your autobiography is an account of your life, which you write yourself.
- autocatharsis — a therapeutic process designed to free unconscious disturbances by having the patient write about his or her experiences, impressions, etc.
- autoeroticism — the arousal and use of one's own body as a sexual object, as through masturbation
- autographical — Relating to, or used in, the process of autography.
- automatograph — a device for recording involuntary bodily movements.
- autoprojector — (theory) A self-applicable partial evaluator.
- autoradiogram — autoradiograph
- autoresponder — A program that automatically generates a set response to all messages sent to a particular e-mail address.
- autorickshaws — Plural form of autorickshaw.
- autumn crocus — a liliaceous plant, Colchicum autumnale, of Europe and N Africa having pink or purplish autumn flowers
- averruncation — the act of averting or turning away
- bachelor flat — a flat lived in, or intended for a bachelor
- bachelorettes — Plural form of bachelorette.
- back to front — If you are wearing something back to front, you are wearing it with the back of it at the front of your body. If you do something back to front, you do it the wrong way around, starting with the part that should come last.
- backformation — Alternative spelling of back-formation.
- backing store — a computer storage device, usually a disk, that provides additional storage space for information so that it can be accessed and referred to when required and may be copied into the processor if needed
- backwardation — the difference between the spot price for a commodity, including rent and interest, and the forward price
- bacteriocidal — Alternative spelling of bactericidal.
- bacteriogenic — Caused by bacteria.
- bacteriologic — a branch of microbiology dealing with the identification, study, and cultivation of bacteria and with their applications in medicine, agriculture, industry, and biotechnology.