| ontology |
the philosophical study of existence and the nature of reality. |
| on top |
at the highest point (of something), or on the uppermost surface (esp. of something that is tall). [3 definitions] |
| on top of |
in total control. [3 definitions] |
| onto something |
having in mind a unique thought with great potential, or having invented or discovered something with great possibility. |
| onus |
an unwanted but necessary task; burden. [2 definitions] |
| on view |
in a place visible to the public; on display. |
| onward |
toward a point or position ahead, as in space or time. [2 definitions] |
| on welfare |
receiving public aid because of poverty, hardship, or need. |
| -onym |
name; word. |
| onyx |
a kind of banded multi-colored quartz, used as a semiprecious stone. [2 definitions] |
| oo- |
ovum; egg. |
| oocyte |
a cell in the earliest stage of transformation into a female egg; immature egg. |
| oodles |
(informal; sometimes used with a sing. verb) a great quantity. |
| oogenesis |
the process whereby female egg cells are produced. |
| oogonium |
a reproductive cell in some algae and fungi. [2 definitions] |
| ooh |
used to express pleasure, happy surprise, or amazement. [3 definitions] |
| oolite |
a variety of limestone made up of small spherical grains. [2 definitions] |
| oology |
the scientific study of birds' eggs. |
| oolong |
a dark tea of China and Taiwan that is partly fermented before it is dried. |
| oophorectomy |
a surgical operation involving the removal of one or both ovaries; ovariotomy. |
| oophoritis |
inflammation of one or both ovaries; ovaritis. |