unlike quantities

Webster's Dictionary (GCIDE)

1.Not like; dissimilar; diverse; having no resemblance; as, the cases are unlike. [1913 Webster]

2.Not likely; improbable; unlikely. [Obsoles.] [1913 Webster]

Unlike quantities (Math.), quantities expressed by letters which are different or of different powers, as a, b, c, a^2, a^3, x^n, and the like.

Unlike signs (Math.), the signs plus (+) and minus (-). [1913 Webster]