principal

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. First, highest, or foremost in importance, rank, worth, or degree; chief. See Synonyms at chief.
2. adj. Of, relating to, or being financial principal, or a principal in a financial transaction.
3. n. One who holds a position of presiding rank, especially the head of an elementary school or high school.
4. n. A main participant in a situation.
5. n. A person having a leading or starring role.
6. n. The capital or main body of an estate or financial holding as distinguished from the interest or revenue from it.
7. n. A sum of money owed as a debt, upon which interest is calculated.
8. n. Law A person who empowers another to act as his or her representative.
9. n. Law The person having prime responsibility for an obligation as distinguished from one who acts as surety or as an endorser.
10. n. Law One who commits or is an accomplice to a crime.
11. n. Architecture Either of a pair of inclined timbers forming the sides of a triangular truss for a pitched roof.

Century Dictionary and Cyclopedia

1. 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.
2. Of or pertaining to a prince; princely.
3. Synonyms Leading, great, capital, cardinal, supreme.
4. 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.
5. n. A governor or presiding officer; one who is Chief in authority. ; ; . Specifically, the head of an institution of learning: a title used in colleges or universities in Scotland, Canada, and other parts of the British empire
6. 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.
7. n. A person for whom another becomes surety; one who is liable for a debt in the first instance.
8. n. In testamentary and administration law, the corpus or capital of the estate, in contradistinction to the income. Thus, under a gift of the income of stock to A for life, and on A's death the stock to B, it is often a contested question whether a stock dividend, as distinguished from a money dividend, is income or principal.
9. 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. A principal in the first degree is the absolute perpetrator of the act which constitutes the crime, whether he does it with his own hand or by the hand of an innocent third person, the third person being ignorant of the character of the act perpetrated. A principal in the second degree is a person who, without actually participating in the act itself, is present, aiding and encouraging the person who commits the act. See accessory.
10. 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.
11. 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. Such a stop is commonly the one in which the temperament is first set in tuning, and from which other stops are tuned. In Germany the open diapason is called the principal, and the octave is called the octave principal.
12. 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.
13. n. In music: The subject of a fugue: opposed to answer.
14. n. A soloist or other leading performer.
15. n. Same as principal rafter. See rafter.
16. 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.
17. n. One of the turrets or pinnacles of waxwork and tapers with which the posts and center of a hearse were formerly crowned.
18. n. An important personal belonging; an heirloom.
19. n. In ornithology, one of the primaries.
20. n. A main truss, as of a roof, where there may be many principals.
21. 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.

Wiktionary

1. adj. Primary; most important.
2. n. finance, uncountable The money originally invested or loaned, on which basis interest and returns are calculated.
3. n. North America, Australia, New Zealand The chief administrator of a school.
4. n. UK, Scotland, Canada The chief executive and chief academic officer of a university or college.
5. n. law One who directs another (the agent) to act on one′s behalf.
6. n. law The primary participant in a crime.
7. n. A company represented by a salesperson.
8. n. ​ (North America) A partner or owner of a business.
9. n. music A diapason, a type of organ stop on a pipe organ.

GNU Webster's 1913

1. adj. Highest in rank, authority, character, importance, or degree; most considerable or important; chief; main.
2. adj. A Latinism, obsolete Of or pertaining to a prince; princely.
3. n. A leader, chief, or head; one who takes the lead; one who acts independently, or who has controlling authority or influence; ; -- distinguished from a subordinate, abettor, auxiliary, or assistant.
4. n. The chief actor in a crime, or an abettor who is present at it, -- as distinguished from an accessory.
5. n. A chief obligor, promisor, or debtor, -- as distinguished from a surety.
6. n. One who employs another to act for him, -- as distinguished from an agent.
7. n. obsolete, obsolete A thing of chief or prime importance; something fundamental or especially conspicuous.
8. n. (Com.), obsolete, obsolete A capital sum of money, placed out at interest, due as a debt or used as a fund; -- so called in distinction from interest or profit.
9. n. (Arch. & Engin.), obsolete, obsolete The construction which gives shape and strength to a roof, -- generally a truss of timber or iron, but there are roofs with stone principals. Also, loosely, the most important member of a piece of framing.
10. n. (Mus.), obsolete, obsolete In English organs the chief open metallic stop, an octave above the open diapason. On the manual it is four feet long, on the pedal eight feet. In Germany this term corresponds to the English open diapason.
11. n. (O. Eng. Law), obsolete, obsolete A heirloom; a mortuary.
12. n. obsolete, obsolete The first two long feathers of a hawk's wing.
13. n. obsolete, obsolete One of turrets or pinnacles of waxwork and tapers with which the posts and center of a funeral hearse were formerly crowned.
14. n. obsolete A principal or essential point or rule; a principle.

WordNet 3.0

1. n. the major party to a financial transaction at a stock exchange; buys and sells for his own account
2. adj. most important element
3. n. the educator who has executive authority for a school
4. n. the original amount of a debt on which interest is calculated
5. n. an actor who plays a principal role
6. n. (criminal law) any person involved in a criminal offense, regardless of whether the person profits from such involvement
7. n. capital as contrasted with the income derived from it