Word:

# Principal

Prin´ci`pal
a.1.Highest in rank, authority, character, importance, or degree; most considerable or important; chief; main; as, the principal officers of a Government; the principal men of a state; the principal productions of a country; the principal arguments in a case.
Wisdom is the principal thing.
2.Of or pertaining to a prince; princely.
 Principal axis See Axis of a curve, under Axis.
 Principal axes of a quadric (Geom.) three lines in which the principal planes of the solid intersect two and two, as in an ellipsoid.
 Principal challenge (Law) See under Challenge.
 Principal plane a - See Plane of projection (a), under Plane.
 Principal of a quadric (Geom.) three planes each of which is at right angles to the other two, and bisects all chords of the quadric perpendicular to the plane, as in an ellipsoid.
 Principal point (Persp.) the projection of the point of sight upon the plane of projection.
 Principal ray (Persp.) the line drawn through the point of sight perpendicular to the perspective plane.
 Principal section (Crystallog.) a plane passing through the optical axis of a crystal.
n.1.A leader, chief, or head; one who takes the lead; one who acts independently, or who has controlling authority or influence; as, the principal of a faction, a school, a firm, etc.; - distinguished from a subordinate, abettor, auxiliary, or assistant.
2.(Law) The chief actor in a crime, or an abettor who is present at it, - as distinguished from an accessory.
3.(Com.) A thing of chief or prime importance; something fundamental or especially conspicuous.
 Noun 1 principal - the original amount of a debt on which interest is calculated 2 principal - the educator who has executive authority for a school; "she sent unruly pupils to see the principal"Synonyms: head teacher, school principal, head 3 principal - an actor who plays a principal roleSynonyms: star, lead 4 principal - capital as contrasted with the income derived from itSynonyms: corpus, principal sum 5 principal - the major party to a financial transaction at a stock exchange; buys and sells for his own accountSynonyms: dealer Adj. 1 principal - most important element; "the chief aim of living"; "the main doors were of solid glass"; "the principal rivers of America"; "the principal example"; "policemen were primary targets"Synonyms: chief, main, primary