Noah Webster's New International Dictionary of the English Language
1. (n.) The act of differing; the state or measure of being different or unlike; distinction; dissimilarity; unlikeness; variation; as, a difference of quality in paper; a difference in degrees of heat, or of light; what is the difference between the innocent and the guilty?
2. (n.) Disagreement in opinion; dissension; controversy; quarrel; hence, cause of dissension; matter in controversy.
3. (n.) That by which one thing differs from another; that which distinguishes or causes to differ; mark of distinction; characteristic quality; specific attribute.
4. (n.) Choice; preference.
5. (n.) An addition to a coat of arms to distinguish the bearings of two persons, which would otherwise be the same. See Augmentation, and Marks of cadency, under Cadency.
6. (n.) The quality or attribute which is added to those of the genus to constitute a species; a differentia.
7. (n.) The quantity by which one quantity differs from another, or the remainder left after subtracting the one from the other.
8. (v. t.) To cause to differ; to make different; to mark as different; to distinguish.