pat·ter 1 
(pătər)
(pătər)v. pat·tered, pat·ter·ing, pat·ters
v.intr.
1. To make a quick succession of light soft tapping sounds: Rain pattered steadily against the glass.
2. To move with quick, light, softly audible steps.
v.tr.
To cause to patter.
n.
A quick succession of light soft tapping sounds: the patter of rain on the rooftops.
[Frequentative of PAT1.]