שָׁלַשׁ shâlash (H8027)

to be (causatively, make) triplicate (by restoration, in portions, strands, days or years)

1) to do a third time, do three times, divide in three parts 1a) (Piel) to do a third time, divide into three parts 1b) (Pual) to be three years of age, be threefold

a primitive root perhaps originally to intensify, i.e. treble; but apparently used only as denominative from שָׁלוֹשׁ (H7969),