verb, -at⋅ed, -at⋅ing.| 1. | to form or mark differently from other such things; distinguish. |
| 2. | to change; alter. |
| 3. | to perceive the difference in or between. |
| 4. | to make different by modification, as a biological species. |
| 5. | Mathematics. to obtain the differential or the derivative of. |
| 6. | to become unlike or dissimilar; change in character. |
| 7. | to make a distinction. |
| 8. | Biology. (of cells or tissues) to change from relatively generalized to specialized kinds, during development. |
