group; team / set; unit / combination

a fountainhead (source of a river) / a source, origin

need, necessity / essential

key, important point / essential piece of something, requirement

the pin or rivet holding the spines of a folding fan together / (by extension) a pivot, cornerstone, keystone / a pin, often decorated, holding the handle to the tang of a katana

a female given name

(archaic, possibly obsolete) the pin or rivet holding the spines of a folding fan together

(archaic, possibly obsolete) fortress, redoubt / (archaic, possibly obsolete) important point, key

alive / lively / (of a machine or device) on; active; in operation

life