a three pronged object
trident
a ten-footed creature
decapod
a series of three books or plays
trilogy
quintuplet
one of five babies born at one birth
a polygon having five sides
pentagon
a period of 100 years
century
prim, prin, proto
first
rota/volv
turn
cor
heart
rect/reg
king
uni/mono
one
bi/du
two
tri, quad, quint, pent, dec, cent
numbers