Primitive sheath

Primitive Prim"i*tive, a. [L. primitivus, fr. primus the first: cf. F. primitif. See {Prime}, a.] 1. Of or pertaining to the beginning or origin, or to early times; original; primordial; primeval; first; as, primitive innocence; the primitive church. ``Our primitive great sire.'' --Milton. [1913 Webster]

2. Of or pertaining to a former time; old-fashioned; characterized by simplicity; as, a primitive style of dress. [1913 Webster]

3. Original; primary; radical; not derived; as, primitive verb in grammar. [1913 Webster]

{Primitive axes of co["o]rdinate} (Geom.), that system of axes to which the points of a magnitude are first referred, with reference to a second set or system, to which they are afterward referred.

{Primitive chord} (Mus.), that chord, the lowest note of which is of the same literal denomination as the fundamental base of the harmony; -- opposed to derivative. --Moore (Encyc. of Music).

{Primitive circle} (Spherical Projection), the circle cut from the sphere to be projected, by the primitive plane.

{Primitive colors} (Paint.), primary colors. See under {Color}.

{Primitive Fathers} (Eccl.), the acknowledged Christian writers who flourished before the Council of Nice, A. D. 325. --Shipley.

{Primitive groove} (Anat.), a depression or groove in the epiblast of the primitive streak. It is not connected with the medullary groove, which appears later and in front of it.

{Primitive plane} (Spherical Projection), the plane upon which the projections are made, generally coinciding with some principal circle of the sphere, as the equator or a meridian.

{Primitive rocks} (Geol.), primary rocks. See under {Primary}.

{Primitive sheath}. (Anat.) See {Neurilemma}.

{Primitive streak} or {Primitive trace} (Anat.), an opaque and thickened band where the mesoblast first appears in the vertebrate blastoderm. [1913 Webster]

Syn: First; original; radical; pristine; ancient; primeval; antiquated; old-fashioned. [1913 Webster]