| opéra bouffe |
a comic, farcical, or satirical opera. |
| opéra comique |
opera with spoken dialogue in addition to musical solos and ensembles. |
| opera glasses |
a small pair of low-power binoculars, used to get a better view of stage performers. |
| opera hat |
a man's collapsible top hat. |
| opera house |
a theater, esp. one in which operas are performed. |
| operant |
having some effect; operating. [4 definitions] |
| opera seria |
eighteenth-century Italian dramatic opera, characterized by frequent arias and classical or mythological themes. |
| operate |
to function in a correct or effective manner, as a machine. [5 definitions] |
| operatic |
characteristic of or pertaining to the opera. [3 definitions] |
| operating system |
in computing, the software that controls and manages all aspects of a computer's operation, including the execution of application programs; the functioning of computer hardware; data input and output; the timing of and allocation of resources to the execution of multiple, simultaneous tasks; the physical storage and location of data; and computer security. Users interact with the operating system though a graphical user interface. |
| operation |
the act or process of operating or functioning. [5 definitions] |
| operational |
being used or capable of being used; functional. [2 definitions] |
| operationalize |
to put into operation; make operational. |
| operations research |
the systematic mathematical or scientific analysis of an operation, policy, or process to improve its effectiveness or efficiency. |
| operative |
one who is employed in a particular kind of work, esp. in industry. [6 definitions] |
| operator |
one who controls functions, operations, or activities, as of machines or businesses. [4 definitions] |
| operatorless |
combined form of operator. |
| operculum |
in biology, an organ or organ part that serves as a lid, flap, or cover. |
| operetta |
a short light, usu. humorous opera, often with dialogue that is spoken as well as sung. |
| ophidian |
designating the biological suborder that comprises snakes. [2 definitions] |
| ophiolatry |
the attribution of divine power to snakes; worship of snakes. |