SOME DEFINITIONS

de·fin·i·en·dum –noun, plural
1. something that is or is to be defined, esp. the term at the head of a dictionary entry.
2. Logic. an expression to be defined in terms of another expression previously defined.

de·fin·i·ens –noun, plural
1. something that defines, esp. the defining part of a dictionary entry.
2. Logic. an expression in terms of which another may be adequately defined.