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. |
pa'anga |
the chief monetary unit of Tonga, equaling one hundred seniti. |
Pablo Picasso |
a Spanish painter and sculptor (b.1881--d.1973). |
Pablum |
trademark for a smooth, bland baby cereal. [2 definitions] |
pabulum |
a soft substance that serves to nourish. [2 definitions] |
PAC |
abbreviation of "political action committee." |
pac |
an insulated, waterproof boot designed for wear in extreme cold. [3 definitions] |