Summary: The English word root *fect* comes from a Latin verb meaning 'make' or 'do.' Some common English words that come from *fect* include in[*fect*], per[*fect*], and de[*fect*]. A way to per[*fect*]ly remember *fect* is that something per[*fect*] is so well 'done' that it cannot be 'made' any better.
