12-letter words containing i, a, t, r, o
- antitumoural — acting against or upon tumours
- anton sailer — Anton [ahn-tohn] /ˈɑn toʊn/ (Show IPA), ("Toni") 1935–2009, Austrian skier.
- aortic valve — a semilunar valve between the aorta and the left ventricle of the heart that prevents the blood from flowing back into the left ventricle.
- aortographic — relating to an aortography or aortography
- aperiodicity — not periodic; irregular.
- aphoristical — Alternative form of aphoristic.
- apochromatic — (of a lens) almost free from spherical and chromatic aberration
- 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.
- apparitional — of or relating to an apparition or apparitions; ghostly, spectral
- apperception — the attainment of full awareness of a sensation or idea
- appoggiatura — an ornament consisting of a nonharmonic note (short or long) preceding a harmonic one either before or on the stress
- apportioning — Present participle of apportion.
- appreciation — Appreciation of something is the recognition and enjoyment of its good qualities.
- appreciators — to be grateful or thankful for: They appreciated his thoughtfulness.
- appreciatory — appreciative.
- approbations — approval; commendation.
- appropriated — suitable or fitting for a particular purpose, person, occasion, etc.: an appropriate example; an appropriate dress.
- appropriates — suitable or fitting for a particular purpose, person, occasion, etc.: an appropriate example; an appropriate dress.
- appropriator — suitable or fitting for a particular purpose, person, occasion, etc.: an appropriate example; an appropriate dress.
- approximated — near or approaching a certain state, condition, goal, or standard.
- approximates — near or approaching a certain state, condition, goal, or standard.
- approximator — Something that approximates.
- apricot tart — a pastry case filled with apricots
- apron string — a string for tying an apron on
- arbitrations — Plural form of arbitration.
- arborization — a branching treelike appearance in certain fossils and minerals
- archaization — Process of becoming or turning something more archaic.
- archegoniate — having archegonia
- archeologist — archaeology.
- archibenthos — the ocean bottom between the littoral and abyssal zones: from depths of approximately 200 feet (60 meters) to 3300 feet (1000 meters).
- arctic ocean — the ocean surrounding the North Pole, north of the Arctic Circle. Area: about 14 100 000 sq km (5 440 000 sq miles)
- arctophilist — a collector of teddy bears
- arfvedsonite — a type of hornblende with the composition Na3(Fe,Mg)4FeSi8O22(OH)2
- aristocratic — Aristocratic means belonging to or typical of the aristocracy.
- aristolochia — any of various plants of the genus Aristolochia of the family Aristolochiaceae
- aristophanes — ?448–?380 bc, Greek comic dramatist, who satirized leading contemporary figures such as Socrates and Euripides. Eleven of his plays are extant, including The Clouds, The Frogs, The Birds, and Lysistrata
- aristophanic — 448?–385? b.c, Athenian comic dramatist.
- aristotelian — of or relating to Aristotle or his philosophy
- arithmomania — an obsessive desire to count objects, or a fixation with numbers and calculations
- aromatically — having an aroma; fragrant or sweet-scented; odoriferous.
- arousability — to stimulate sexually.
- arpeggiation — the writing, playing or singing of arpeggios
- arsenopyrite — a white or grey metallic mineral consisting of a sulphide of iron and arsenic that forms monoclinic crystals with an orthorhombic shape: an ore of arsenic. Formula: FeAsS
- art director — a person responsible for the sets and costumes in a film
- art mobilier — small, movable art objects, especially primitive or prehistoric works of art.
- arteriograms — Plural form of arteriogram.
- arteriopathy — Any disease of the arteries.