intra- Look up intra- at
word-forming element meaning "within, inside, on the inside," from Latin preposition intra "on the inside, within, in, into;" of time, "during, in the course of," related to inter "between," from PIE *en-t(e)ro-, from root *en "in" (see in). Commonly opposed to extra-, and compare inter-. The use of intra as a prefix was rare in classical Latin.