Where does “palpus” come from?

palpus (New Latin) comes from Latin palpō, from Latin -ō, from Proto-Indo-European -ō — Derives nouns from roots.

Ancestry of “palpus”, step by step

Step	Language	Word	Meaning
1	Latin	palpō	to touch softly, stroke, pat
2	Latin	-ō	suffixed to nouns or adjectives. Originally a-stem nouns. Later extended to nouns with other stems. Forms regular first-conjugation verbs
3	Proto-Indo-European	-ō	Derives nouns from roots