9-letter words containing o, y
- antiphony — the antiphonal singing of a musical composition by two choirs
- antiroyal — opposed to the monarchy
- antistory — a story which does not conform to the established conventions of storytelling
- antonymic — having the opposite meaning, relating to antonyms
- anxiously — full of mental distress or uneasiness because of fear of danger or misfortune; greatly worried; solicitous: Her parents were anxious about her poor health.
- anybodies — a person of some importance: If you're anybody, you'll receive an invitation.
- aphyllous — (of plants) having no leaves
- apocrypha — the 14 books included as an appendix to the Old Testament in the Septuagint and the Vulgate but not included in the Hebrew canon. They are not printed in Protestant versions of the Bible
- apoenzyme — a protein component that together with a coenzyme forms an enzyme
- apomorphy — (systematics): A derived characteristic of a clade. Any feature novel to a species and its descendants.
- apophyges — Plural form of apophyge.
- apophyses — Plural form of apophyse.
- apophysis — a process, outgrowth, or swelling from part of an animal or plant
- apriority — the quality or fact of being a priori
- aqueously — in water, or by means of water
- arbor day — a tree-planting day observed individually by the states of the U.S., usually in spring
- archology — the study of the origins of things
- arduously — requiring great exertion; laborious; difficult: an arduous undertaking.
- areostyle — (of columned buildings) having a wide intercolumniation equal to four or more diameters of one of the columns
- army worm — any of the larvae of certain noctuid moths, esp. of the moth (Pseudaletia unipuncta) of which the caterpillar is dark-striped green and yellow: these larvae travel in large groups, ruining crops and grass
- armyworms — Plural form of armyworm.
- arrogancy — offensive display of superiority or self-importance; overbearing pride.
- arrow key — (hardware) One of four keys on a keyboard marked with arrows pointing up, down, left and right. The arrow keys are used for such things as moving the cursor in a text document, for moving the input focus between the fields of a form or sometimes for scrolling a picture.
- aryballos — a small narrow-necked vessel or bottle shaped like a sphere, used in ancient Greece to store oil or perfume
- arylation — to introduce one or more aryl groups into (a compound).
- arytenoid — denoting either of two small cartilages of the larynx that are attached to the vocal cords
- assay ton — a unit of weight used in assaying ore, equivalent to 29.167 grams.
- assertory — characterized by or relating to declaration or affirmation
- astonying — Present participle of astony.
- astrocyte — any of the star-shaped cells in the tissue supporting the brain and spinal cord (neuroglia)
- astrology — Astrology is the study of the movements of the planets, sun, moon, and stars in the belief that these movements can have an influence on people's lives.
- astronomy — Astronomy is the scientific study of the stars, planets, and other natural objects in space.
- asymptote — a straight line that is closely approached by a plane curve so that the perpendicular distance between them decreases to zero as the distance from the origin increases to infinity
- asyndeton — the omission of a conjunction between the parts of a sentence
- asystoles — Plural form of asystole.
- asystolic — Pertaining to asystole.
- atheology — a resistance or aversion to theology
- athrocyte — a cell that is able to receive and store matter
- atmolysis — a method of separating gases that depends on their differential rates of diffusion through a porous substance
- atmometry — the science of measuring the rate at which water evaporates.
- atomicity — the state of being made up of atoms
- atomology — (dated) The doctrine of atoms.
- atonality — absence of or disregard for an established musical key in a composition
- atonicity — lack of tone; atony.
- atoningly — in an expiating manner
- atriotomy — (medicine) The surgical opening of an atrium.
- attorneys — Plural form of attorney.
- audiology — the scientific study of hearing, often including the treatment of persons with hearing defects
- aulophyte — a free-living plant growing on or in another plant.
- auriscopy — (medicine) Examination of the ear using an auriscope.