also pitter-pat, 1520s; imitative. As a noun from 1580s.
Entries linking to pit-a-pat
pitter-patter n.
early 15c., "rapid repetition of words," from a rhyming reduplication of patter (v.2). As "alternating light beating sounds," 1670s, from patter (v.1). As a verb in this sense by 1708. Compare pit-a-pat.