| on the spot |
at once; immediately. [2 definitions] |
| on the spur of the moment |
without much thought; on a sudden impulse. |
| on the whole |
all things considered; in general; for the most part. |
| on tiptoe |
standing or walking on the toes, esp. to proceed quietly or cautiously. [2 definitions] |
| onto |
to a position on or on top of. [2 definitions] |
| on top of |
in total control. [3 definitions] |
| onward |
toward a point or position ahead, as in space or time. [2 definitions] |
| ooze1 |
to seep out gradually and slowly, as liquid, gas, or sound may do. [7 definitions] |
| 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. |