quinque-
Pentateuch
pentacle
pentagon
pentagram
pentahedron
pentalogy
pentameter
pentathlete
pentathlon
pentatonic
pentomino
aqua fortis
dinitronaphthalene
field-grade
flag
four-headed
guanidine
iodate
leaches
mercurous
molybdate
n-hexane
neck-high
nitroguanidine
nitronium
nitroprusside
non-real
red-and-white-striped
sixteen-foot
styphnate
uranyl
useable
wood pulp