12-letter words containing a, s, o, r
- and so forth — and so on; and other such things; et cetera
- androgenesis — a type of reproduction in insects and plants involving the development of an embryo that contains only paternal chromosomes
- androscoggin — a river flowing from NE New Hampshire through SW Maine into the Kennebec River. 171 miles (275 km) long.
- androsterone — an androgenic steroid hormone produced in the testes. Formula: C19H30O2
- anemochorous — (of a fruit, seed, or spore) adapted for dispersion by wind.
- anemotropism — orientation in response to a current of air.
- angiocarpous — being or having fruit contained in a vessel such as a shell
- angiosarcoma — a rare, malignant tumour which grows rapidly in the blood vessels
- animatronics — a branch of film and theatre technology that combines traditional puppetry techniques with electronics to create lifelike animated effects
- anisomorphic — differing in the semantic scope of terms referring to the real world: for instance, English and Russian are anisomorphic with regard to colour terms, English treating light blue and navy blue as shades of one colour but Russian treating these two shades as unrelated
- anisothermal — (thermodynamics) Of or pertaining to a system that is not in thermal equilibrium, that does not have a single fixed temperature.
- anisotropies — Plural form of anisotropy.
- anisotropism — the state of being anisotropic
- ankylosaurus — a plant-eating dinosaur of the Cretaceous period that had a tail resembling a club and a body covering of thick scales
- annunciators — Plural form of annunciator.
- anorthoclase — a variety of microcline, rich in sodium and sometimes having a play of color: sometimes considered a variety of orthoclase.
- anorthositic — resembling or consisting of anorthosite
- anotherguess — of a different type or kind; different
- ansate cross — ankh
- anteriorness — The state or quality of being anterior.
- anthocarpous — resembling or pertaining to an anthocarp
- anthologiser — Alternative spelling of anthologizer.
- anti-strophe — the part of an ancient Greek choral ode answering a previous strophe, sung by the chorus when returning from left to right.
- anticonsumer — opposed to consumerism
- antiestrogen — any of several major female sex hormones produced primarily by the ovarian follicles of female mammals, capable of inducing estrus, developing and maintaining secondary female sex characteristics, and preparing the uterus for the reception of a fertilized egg: used, especially in synthetic form, as a component of oral contraceptives, in certain cancer treatments, and in other therapies.
- antigropelos — waterproof leggings used to protect against mud
- antineutrons — Plural form of antineutron.
- antiroyalism — Opposition to royals or royalism.
- antiroyalist — opposed to the monarchy
- antistrophes — Plural form of antistrophe.
- antistrophic — Of or pertaining to an antistrophe.
- antistrophon — an argument that is retorted against an opponent
- anton sailer — Anton [ahn-tohn] /ˈɑn toʊn/ (Show IPA), ("Toni") 1935–2009, Austrian skier.
- aphoristical — Alternative form of aphoristic.
- aphrodisiacs — Plural form of aphrodisiac.
- apostle bird — a gregarious grey-and-brown Australian nest-building bird, Struthidea cinerea
- apostrophise — to address by apostrophe.
- apostrophize — to address an apostrophe to
- apothecaries — Plural form of apothecary.
- appreciators — to be grateful or thankful for: They appreciated his thoughtfulness.
- apprehension — Apprehension is a feeling of fear that something bad may happen.
- appressorium — a flattened hypha of a parasitic fungus that penetrates the host tissues
- approbations — approval; commendation.
- appropriates — suitable or fitting for a particular purpose, person, occasion, etc.: an appropriate example; an appropriate dress.
- approximates — near or approaching a certain state, condition, goal, or standard.
- apron string — a string for tying an apron on
- araeosystyle — (of columned buildings) having an alternately very wide and very narrow intercolumniation
- araneomorphs — Plural form of araneomorph.
- arbitrations — Plural form of arbitration.
- arborescence — treelike in size and form.