principal

A portion of your mortgage payment goes to reduce the principal, and the rest covers interest.

The important administrative figure to the teacher is the school principal.

Unlike the students, Principal Robertson, who now resided almost alone in the College, continued to use the accustomed route on his visits to the Old Town; and it “became the joke of the day that from being the principal gate it had become only a gate for the Principal.”⁵

When an attorney represents a client, the client is the principal who permits the attorney, the client′s agent, to act on the client′s behalf.

Coordinate term: accessory

a birde whose principals be scarce growne out

Set two classes of monitors to question each other; so that one may try to outquestion the other. Explain to them the principal of every subject they have to teach.