| opal |
a variously colored, often iridescent, hydrated form of silica often used as a semiprecious stone. |
| opaque |
not allowing light to pass through. (Cf. transparent.) [6 definitions] |
| OPEC |
abbreviation of "Organization of Petroleum Exporting Countries." |
| open |
allowing entry or access; not shut, enclosed, or fastened. [27 definitions] |
| opener |
someone or something that opens. [3 definitions] |
| opening |
the act, process, or result of making open or causing to become open. [6 definitions] |
| openly |
in a way that involves no hiding or lying. |
| open-minded |
not having preconceptions or prejudgments; receptive; tolerant; impartial. |
| opera1 |
a dramatic work set to music, with an accompaniment by an orchestra. [3 definitions] |
| operate |
to function in a correct or effective manner, as a machine. [5 definitions] |
| operation |
the act or process of operating or functioning. [5 definitions] |
| operator |
one who controls functions, operations, or activities, as of machines or businesses. [4 definitions] |
| operetta |
a short light, usu. humorous opera, often with dialogue that is spoken as well as sung. |
| ophthalmologist |
a doctor who specializes in the study and treatment of eye diseases. |
| ophthalmology |
the medical study of the eye, its diseases, and their treatments. |
| opinion |
what one thinks about a matter, esp. a judgment not necessarily based on fact alone. [5 definitions] |
| opossum |
any of a number of American marsupials that are active at night and live in trees. [2 definitions] |
| opponent |
one who opposes; antagonist; foe. |
| opportunity |
a chance that makes something possible or that may bring about some benefit. [2 definitions] |
| oppose |
to think, act, or be against; resist or obstruct. [3 definitions] |
| opposed |
not in favor of; against. |