"perhaps, possibly, maybe," mid-14c., parchaunce, from Old French par cheance, literally "by chance." With Latin per substituted c. 1400 for French cognate par. See per + chance (n.).
To sleep, perchance to dream...
perceptible
perception
perceptive
perceptual
perch
perchance
Percheron
percipience
percipient
Percocet
percolate