principal part in Latin

Any of the forms of a word which contain its stem(s) in the simplest form, or such a form that, when taken with all the other principal parts (showing various inflections), allows the entire paradigm to be derived.

Any of the forms of a word which contain its stem(s) in the simplest form, or such a form that, when taken with all the other principal parts (showing various inflections), allows the entire paradigm to be derived.

(obsolete) Any one of however many parts of speech regarded as the most fundamental or indispensable.