1520s, "something that is thrust in or fixed or pierced," from pitch (v.1). Sense of "slope, degree, inclination" is from 1540s; from 1550s as "highest point or reach;" from 1620s as "height" in general. Meaning "height of an arched roof above the floor" is by 1610s.
Meaning "a throw, a toss, an act of throwing" is attested by 1833. Meaning "act of plunging headfirst" is from 1762. The musical sense of "characteristic of a sound or tone that depends upon relative rapidity of vibration" is from 1590s, also "particular tonal standard." See pitch (v.1) for sense evolutions, but the connection of many of these is obscure.
Some noun senses are from the older sense of pitch as "to thrust in, drive (a stake)." Thus, in cricket, "place where the wickets are pitched" (1871).
Sales pitch in the modern commercial advertising sense is from 1943, American English; pitch in the sense of "tedious or inflated sales talk" is attested by 1876, perhaps ultimately from the baseball sense. Pitch also was "place on which to pitch or set up a booth for sale or exhibition" (by 1851).
"thick, tenacious, resinous substance obtained from tar or turpentine, wood tar," late 12c., pich, piche, from Old English pic "pitch," from a Germanic borrowing (compare Old Saxon and Old Frisian pik, Middle Dutch pik, Dutch pek, Old High German pek, German Pech, Old Norse bik) of Latin pix (genitive picis) "pitch" (source of Old French poiz), from PIE root *pik- "pitch" (source also of Greek pissa (Attic pitta), Lithuanian pikis, Old Church Slavonic piklu "pitch," Russian peklo "scorching heat, hell").
The English word was improperly applied to sap from pine bark from late 14c. As a type of blackness from c. 1300. Pitch-black "as black as pitch" is attested from 1590s; pitch-dark "as dark as pitch, very dark" from 1680s.
c. 1200, "to thrust (something) in, drive (a stake), pierce with a sharp point," senses now obsolete, also "to fasten, settle," probably from an unrecorded Old English *piccean, related to prick (v.). The original past tense was pight.
The sense of "set upright" (mid-13c.) as in pitch a tent (late 13c.), is from the notion of driving or thrusting the pegs into the ground. The meaning "incline forward and downward" is from 1510s. The intransitive sense of "to plunge or fall headlong" is by 1680s, probably from the use with reference to ships (see below) extended to persons, animals, etc.
The meaning "to throw, fling, hurl, toss" (a ball, a person, hay, etc.) evolved by late 14c. from that of "hit the mark." Specifically in baseball, "to hurl (the ball) to the batter," by 1868.
Musical sense of "determine or set the key of" is by 1630s. Of ships, "to plunge with alternate fall and rise of the bow and stern" as in passing over waves, 1620s.
To pitch in "work vigorously" is from 1847, perhaps from farm labor. A pitched battle is one in which the armies are previously drawn up in form, with a regular disposition of the forces (from the verb in the sense of "to fix or set in order, arrange," late 15c.). Related: Pitched.
"to smear or cover with pitch," Middle English pichen, from Old English pician, from the source of pitch (n.2).