"a throb, a beat," early 14c., from Old French pous, pulse (late 12c., Modern French pouls) and directly from Latin pulsus (in pulsus venarum "beating from the blood in the veins"), past participle of pellere "to push, drive," from PIE root *pel- (5) "to thrust, strike, drive." Extended usages from 16c. Figurative use for "life, vitality, essential energy" is from 1530s.
"peas, beans, lentils," late 13c., from Old French pouls, pols and directly from Latin puls "thick gruel, porridge, mush," probably via Etruscan, from Greek poltos "porridge" made from flour, or both the Greek and Latin words are from the same source (see pollen).
"to beat, throb," early 15c., from pulse (n.1) or else from Latin pulsare "to beat, throb," and in part from French. Related: Pulsed; pulsing.