cub
Spanishto lie down, recline
About This Root
The root cub comes from Latin cubāre, "to lie down, to recline." (A spelling quirk produces the variant -cumb- in some words, as in recumbent and succumb.) Picture a body resting horizontally — that physical image of lying upon something is the seed of the whole family.
The most important prefix is in- ("on, upon"):
- in- (upon) + cubāre (lie) → incubate: literally to lie upon something. A hen incubates eggs by lying on them to keep them warm until they hatch. The metaphor then expanded: you can incubate an idea (let it sit and develop) or a disease (it lies dormant before symptoms appear).
- incubator: the place or device that does the lying-upon — keeping eggs, premature babies, or even young companies warm and protected while they grow.
- incubus: a demon imagined to lie upon sleepers and crush them (the nightmare sensation of a weight on the chest). From there it became a word for any oppressive, crushing burden.
The same root surfaces in less obvious places: succumb = suc- (under) + cumbere (lie) → to lie down under a force, i.e. to give way or die; recumbent = re- (back) + cumbere → leaning back, lying down.
The unifying picture: something lying upon or lying down. Warmth and nurture when a hen lies on eggs; oppression when a demon lies on a chest; surrender when you lie down under a stronger force.
Note one false friend: Cuban (from the island Cuba) only looks like it belongs here — it has nothing to do with lying down.
Picture a hen lying on her eggs — that's incubate (in- 'upon' + cub 'lie'). Every cub- word is about something lying on or lying down: an incubator keeps it warm, an incubus crushes you in your sleep.
Core Words Deep Dive
The few words from this family worth telling in full — one by one.
in- (upon) + cub (lie) = to lie upon. The literal image is a hen sitting on her eggs to warm them until they hatch. From that, three modern senses radiate: incubate eggs (hatch), incubate an idea (let it develop quietly), and incubate a disease (it lies dormant before symptoms show). All share the picture of something kept warm and waiting to emerge.
incubate + -or (the thing that does it) = the device or place that incubates. Started as an egg-hatching machine, then became the medical unit that keeps premature babies warm and safe. The figurative 'business incubator' borrows exactly that image: a protected environment where a fragile startup is nurtured until it can survive on its own.
in- (upon) + cub (lie) + -us = 'the one who lies upon.' In medieval belief, an incubus was a demon that lay on top of sleeping people, felt as a crushing weight on the chest — the old explanation for sleep paralysis and nightmares. Today it also means any oppressive, suffocating burden (the incubus of debt).