ripo

One root, no seam, and it is worth saying because the shape invites one. Three letters plus the ending is short enough to look like a fragment of something longer. It is not: rip- is the whole root, and there is no ri- prefix and no -po ending in Esperanto for it to have been assembled from. Compare ripeti, to repeat, which is a different root entirely (ripet-) and has nothing to do with bones. Two words that begin with the same three letters and share nothing else - a good reminder that Esperanto's decomposability is a promise about the words that ARE built, not a licence to cut up the ones that are not.

The curved bone, and then everything shaped like one. ReVo gives two senses and the second is generous. Literally, one of the curved bones round the brusto in people and animals; the Genesis line everybody knows is in Esperanto too, Dio konstruis el la ripo virinon. Figuratively, any rib-like structural member: the veins of a leaf, the spokes of an umbrella, the ribs of a ship's hull, the ribs of a vault. Ripita ŝtofo is ribbed fabric, corduroy or a ribbed knit. German splits the anatomy from the shipbuilding with two separate words; Esperanto keeps one and lets the context do it.

On the plate. Ripaĵo with the -aĵ- suffix is the cut of meat: a rib steak, a rack of ribs. That is the same suffix that gave you narkotaĵo in this band and viandaĵo long ago - a concrete thing made of the root.

Where it sits in the body. The human body article has the full anatomy vocabulary. The short version for this neighbourhood: osto is a bone, ripa kaĝo or torako is the ribcage, brusto the chest, koro and pulmo what the cage is for, and spino the backbone the ribs hang off.