Chief; highest in rank, authority, value, or importance; most considerable; main; first: as, the principal officers of a government; the principal points in an argument; the principal products of a country.Of or pertaining to a prince; princely.Synonyms Leading, great, capital, cardinal, supreme.n. A chief or head; one who takes a leading part; one primarily concerned in an action, and not an auxiliary, accessory, assistant, or agent: as, the principals in a duel.n. A governor or presiding officer; one who is Chief in authority. ; ; ;n. In law: A person who, being sui juris, and competent to do an act on his own account, employs another person to do it; the person from whom an agent's authority is derived. Compare master, 2.n. A person for whom another becomes surety; one who is liable for a debt in the first instance.n. In testamentary and administration law, the corpus or capital of the estate, in contradistinction to the income.n. In criminal law, the actor in the commission of a crime; a person concerned in the commission of a crime, whether he directly commits the act constituting the offense or instigates or aids and abets in its commission.n. In com., money bearing interest; a capital sum lent on interest, due as a debt or used as a fund: so called in distinction to interest or profits.n. In organ-building, a stop of the open diapason group, usually giving tones an octave above the pitch of the digitals used, like the octave.n. A musical instrument used in old orchestral music, especially that of Handel — a variety of trumpet, probably having a larger tube than the ordinary tromba.n. In music: The subject of a fugue: opposed to answer.n. A soloist or other leading performer.n. Same as principal rafter. See rafter.n. In the fine arts, the chief motive in a work of art, to which the rest are to be subordinate; also, an original painting or other work of art.n. One of the turrets or pinnacles of waxwork and tapers with which the posts and center of a hearse were formerly crowned.n. An important personal belonging; an heirloom.n. In ornithology, one of the primaries.n. A main truss, as of a roof, where there may be many principals.n. In the Philippine Islands, every member, present or past, of the council of a pueblo; also, a first-born son of a gobernadorcillo or of a cabeza de barangay. See barangay.