These three consonants mean one motion: coming back. Go back to a place, go back over a text, go back to a partner. From that single idea Hebrew builds the verb you say a hundred times a day ("I'll come back"), the rehearsal of a play, the prayer-book for the holidays (the machzor is the cycle of the year), and a refund. Once you hear the loop, every word below stops being a separate item. Every entry is verified against pealim, niqqud included.
The same root runs through the verb system. Each binyan is a voice: it bends the one idea into active, passive, causative or reciprocal. Tap to hear.
The split here is clean: pa'al is the intransitive return (the subject comes back), hif'il is the causative one (you make a thing come back, you give it back). Pi'el takes the same loop into the social world: to court is to keep circling back to someone. The passives nif'al / pu'al / huf'al are not lexicalized for this root.
Same root letters, different noun moulds (mishkalim). The mould tells you the function: who does it, the act of doing it, or the thing produced.
Strip the prefixes, suffixes and vowels. Three consonants remain, and the meaning lives there.