| oystercatcher |
any of several black and white shore birds having strong, reddish beaks with which they open and feed on bivalve mollusks such as oysters. |
| oyster crab |
a small crab that lives as a commensal inside the gill cavities of living oysters and clams. |
| oyster cracker |
a small round soda cracker, usu. eaten with oysters, stews, or soups. |
| oyster plant |
see "salsify." |
| oysters Rockefeller |
broiled oysters served on the half shell topped with spinach, bacon, seasonings, and cream sauce or butter. |
| oz. |
abbreviation of "ounce," or "ounces," a unit of weight equal to one sixteenth of a pound or 28.350 grams in the avoirdupois weight system, and equal to one twelfth of a pound or 31.1051 grams in the apothecaries' weight and the troy weight systems. |
| ozone |
oxygen in the form of molecules with three atoms, created by exposure of oxygen to electrical discharge or ultraviolet radiation, having a sharp smell, and being an effective oxidant for use in bleaching and sterilizing. |
| ozone depletion |
a steady decline in ozone in Earth's stratosphere, or a springtime decline in stratospheric ozone in Earth's polar regions. The primary cause of ozone depletion is man-made chemicals, particularly chlorofluorocarbons (CFCs). |
| ozone hole |
an area in the ozone layer where the ozone becomes thin. There is a large ozone hole over Antarctica and a smaller one over the North Pole. Scientists warn us this is dangerous. |
| ozone layer |
an atmospheric layer between ten and twenty miles above the earth that contains a substantial concentration of ozone, which absorbs ultraviolet radiation from space and prevents some heat loss from the earth; ozonosphere. |
| ozonize |
to treat, combine, or saturate with ozone. [2 definitions] |
| ozonosphere |
see "ozone layer." |
| P1 |
abbreviation of "passing," completed successfully. |
| P2 |
symbol of the chemical element phosphorus. |
| P- |
in the U.S. military, a pursuit plane, such as a P-38 or P-40. |
| p |
the sixteenth letter of the English alphabet. [3 definitions] |
| p. |
abbreviation of "page," one side of a sheet of printed or written paper. [2 definitions] |
| PA1 |
abbreviation of "Pennsylvania," an eastern U.S. state south of New York. |
| Pa |
symbol of the chemical element protactinium. |
| PA2 |
abbreviation of "public address." |
| pa |
(informal) father; papa. |