main

The root main comes from Latin manēre, "to stay, to remain, to dwell." Picture someone who refuses to move — they stay put while everything around them changes. That single idea of staying behind branches into a surprisingly wide family, and the spelling shifts between main / man / mans along the way (the past participle was mānsus).

The most literal branch is simply staying:

- re- (back) + manēre → remain: to stay back, to be left behind. When everyone else leaves, what remains is what stayed.
- From the same idea come remainder and remains — the part that stayed after the rest was taken or used up — and remnant, a small scrap that stayed behind.

Add a prefix that means "all the way through" and staying becomes lasting:

- per- (through, thoroughly) + manēre → permanent: staying all the way through time. Something permanent doesn't just stay for a while — it stays through everything. From here: permanence, impermanent (not staying), and the Buddhist-flavored impermanence (nothing stays).

Now take the place where someone stays — their dwelling:

- mansion literally meant a "place to stay," a dwelling. Over centuries the dwelling got grander, until mansion came to mean a large, luxurious house.
- manor (and manorial) came through Old French from the same "dwelling" idea — the lord's residence and the estate around it.

Two more abstract members:

- in- (within) + manēre → immanent: staying within. In philosophy and theology, something immanent dwells inside the world rather than outside it.
- e- (out) + manēre → emanate: this one inverts the image. The source stays in place while something flows out from it — light emanates from a lamp, calm emanates from a person. The lamp remains; the light leaves.

One honest exception: maintain (and maintainer, maintainable, unmaintained, well-maintained) only looks like it belongs here. It actually comes from Latin manū tenēre — "to hold (tenēre) in the hand (manū)." That main- is the hand (manus), not manēre. The meanings rhyme — keeping something going, holding it steady — which is exactly why the two roots are easy to confuse. We flag those words to the tain (hold) root.

The pattern to remember: across remain, permanent, mansion, immanent, emanate, the constant is something staying in place — and the prefix tells you the rest: back, through, within, or out.