pit ‧ ter-pat ‧ ter /ˈpɪtə ˌpætə $ ˈpɪtər ˌpætər/ BrE AmE adverb literary
[ Date: 1400-1500 ; Origin: From the sound ]
with quick light beats or steps:
Anna’s heart went pitter-patter as she opened the letter.
—pitter-patter noun [singular] :
the pitter-patter of small feet running up the stairs