12-letter words containing a, r, i, o, s
- 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
- arbitrations — Plural form of arbitration.
- archdiocesan — Relating to an archdiocese.
- archdioceses — Plural form of archdiocese.
- archeologist — archaeology.
- archesporial — the primitive cell, or group of cells, that give rise to the cells from which spores are derived.
- archesporium — archespore.
- archibenthos — the ocean bottom between the littoral and abyssal zones: from depths of approximately 200 feet (60 meters) to 3300 feet (1000 meters).
- archipelagos — Plural form of archipelago.
- archosaurian — belonging to or characteristic of the archosaurs
- arctophilist — a collector of teddy bears
- arfvedsonite — a type of hornblende with the composition Na3(Fe,Mg)4FeSi8O22(OH)2
- argillaceous — (of sedimentary rocks and deposits) composed of very fine-grained material, such as clay, shale, etc
- ariel sharon — Ariel, 1928–2014, Israeli military and political leader; prime minister 2001–06.
- 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
- arousability — to stimulate sexually.
- arseniferous — Lb geology Containing or producing arsenic.
- 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
- arsino group — the univalent group H 2 As−.
- arteriograms — Plural form of arteriogram.
- arthroscopic — the use of an arthroscope to diagnose an injury to or disease of a joint or to perform minor surgery on a joint.
- arthrotomies — Plural form of arthrotomy.
- articulators — Plural form of articulator.
- artiodactyls — Plural form of artiodactyl.
- arts council — an organization that provides funding for a variety of arts activities
- aspect ratio — the ratio of width to height of the picture on a television or cinema screen
- aspirational — If you describe someone as aspirational, you mean that they have strong hopes of moving to a higher social status.
- assassinator — a person who assassinates
- assertations — Plural form of assertation.
- assessorship — the occupation, post or duties of a person who assesses, advises, or estimates
- asseveration — the act of asseverating.
- assimilators — Plural form of assimilator.
- assimilatory — characterized by assimilation; assimilating.
- astigmometer — an apparatus for measuring the degree of astigmatism.
- astrobiology — the branch of biology that investigates the possibility of life elsewhere in the universe
- astrochemist — (chemistry, astronomy) A chemist or astronomer whose speciality is astrochemistry.
- astrodynamic — Pertaining to astrodynamics.
- astrological — the study that assumes and attempts to interpret the influence of the heavenly bodies on human affairs.