pitch

The tar sense comes from Old English piċ, from Latin pix, the same root that gives us pine (the tree that oozes resin). The throwing/thrusting sense is a separate word, from Old English *piċċan, related to the ancestor of 'pick.' The adjective, as in 'pitch-black,' likely arose later by back-formation from that phrase itself.

What started as two unrelated Old English words — one for sticky tar, one for thrusting or fastening something — collapsed into a single spelling over time, so that 'pitch' now stretches to cover tar, throwing, musical tone, and sales talk alike.

Pitch (the tar) is a cousin of pine, both tracing back to the same ancient root for resinous trees; French poix and Spanish pegar carry the same tar-and-stick idea in their own languages.