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. 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.
Prin"ci*pal, 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. Hence: (Law) (a) The chief actor in a crime, or an abettor who is
present at it, -- as distinguished from an accessory. (b) A chief
obligor, promisor, or debtor, -- as distinguished from a surety. (c)
One who employs another to act for him, -- as distinguished from an
agent. Wharton. Bouvier. Burrill.
3. A thing of chief or prime importance; something fundamental or
especially conspicuous. Specifically: (a) (Com.) 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. (b) (Arch. & Engin.) 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. (c)
(Mus.) 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. (d) (O. Eng. Law) A heirloom; a mortuary. Cowell. (e) pl. The
first two long feathers of a hawk's wing. Spenser. J. H. Walsh. (f) One
of turrets or pinnacles of waxwork and tapers with which the posts and
center of a funeral hearse were formerly crowned. Oxf. Gloss. (g) A
principal or essential point or rule; a principle. [Obs.]
Prin`ci*pal"i*ty (?), n.; pl. Principalities (#). [L. principalitas
preÎminence, excellence: cf. F. principalitÈ, principautÈ. See
Principal.] 1. Sovereignty; supreme power; hence, superiority;
predominance; high, or the highest, station. Sir P. Sidney.
Your principalities shall come down, even the crown of your glory.
Jer. xiii. 18.
The prerogative and principality above everything else.
Jer. Taylor.
2. A prince; one invested with sovereignty. "Next upstood Nisroch, of
principalities the prime." Milton.
3. The territory or jurisdiction of a prince; or the country which
gives title to a prince; as, the principality of Wales.
Prin"ci*pal*ly (?), adv. In a principal manner; primarily; above all;
chiefly; mainly.
Prin"ci*pal*ness, n. The quality of being principal.
Prin"ci*pate (?), n. [L. principatus: cf. F. principat.] Principality;
supreme rule. [Obs.] Barrow.
||Prin*cip"i*a (?), n. pl. [L. principium. See Principle.] First
||principles; fundamental beginnings; elements; as. Newton's Principia.
Prin*cip"i*al (?), a. Elementary. [Obs.] Bacon.
Prin*cip"i*ant (?), a. [L. principians, p. pr. of principiare to begin,
fr. principium. See Principle.] Relating to principles or beginnings.
[R.] Jer. Taylor.
Prin*cip"i*ate (?), v. t. [See Principiant.] To begin; to initiate.
[Obs.] Sir M. Hale.
Prin*cip`i*a"tion (?), n. Analysis into primary or elemental parts.
[Archaic] Bacon.
Prin"ci*ple (?), n. [F. principe, L. principium beginning, foundation,
fr. princeps, - cipis. See Prince.] 1. Beginning; commencement. [Obs.]
Doubting sad end of principle unsound.
Spenser.
2. A source, or origin; that from which anything proceeds; fundamental
substance or energy; primordial substance; ultimate element, or cause.
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The soul of man is an active principle.
Tillotson.