difference

1. The quality of being different.

   You need to learn to be more tolerant of difference.

2. A characteristic of something that makes it different from something else.

   There are three differences between these two pictures.

3. A disagreement or argument.

   We have our little differences, but we are firm friends.

4. Significant change in or effect on a situation or state.

   It just won't make much difference to me.

5. The result of a subtraction; sometimes the absolute value of this result.

   The difference between 3 and 21 is 18.

6. Choice; preference.
7. An addition to a coat of arms to distinguish two people's bearings which would otherwise be the same. See augmentation and cadency.
8. The quality or attribute which is added to those of the genus to constitute a species; a differentia.
9. (logic circuits) A Boolean operation which is TRUE when the two input variables are different but is otherwise FALSE; the XOR operation (\scriptstyle A \overline B + \overline A B).
10. (relational algebra) the set of elements that are in one set but not another (\scriptstyle A \overline B).

verb

To distinguish or differentiate.