Proto-Indo-European root meaning "to sit."

It forms all or part of: assess; assiduous; assiento; assize; banshee; beset; cathedra; cathedral; chair; cosset; dissident; dodecahedron; Eisteddfod; ephedra; ephedrine; ersatz; icosahedron; inset; insidious; nest; niche; nick (n.) "notch, groove, slit;" nidicolous; nidification; nidus; obsess; octahedron; piezo-; piezoelectric; polyhedron; possess; preside; reside; saddle; sanhedrim; seance; seat; sedan; sedate; (adj.) "calm, quiet;" sedative; sedentary; sederunt; sediment; see (n.) "throne of a bishop, archbishop, or pope;" sessile; session; set (v.); sett; settle (n.); settle (v.); siege; sit; sitz-bath; sitzkrieg; size; soil (n.1) "earth, dirt;" Somerset; soot; subside; subsidy; supersede; surcease; tanist; tetrahedron; Upanishad.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit a-sadat "sat down," sidati "sits," nidah "resting place, nest;" Old Persian hadis "abode;" Greek ezesthai "to sit," hedra "seat, chair, face of a geometric solid;" Latin sedere "to sit; occupy an official seat, preside; sit still, remain; be fixed or settled," nidus "nest;" Old Irish suide "seat, sitting," net "nest;" Welsh sedd "seat," eistedd "sitting," nyth "nest;" Old Church Slavonic sežda, sedeti "to sit," sedlo "saddle," gnezdo "nest;" Lithuanian sėdėti "to sit;" Russian sad "garden," Lithuanian sodinti "to plant;" Gothic sitan, Old English sittan "to sit."

"person appointed," 1768, after French appointé, from apointer "arrange, settle, place;" see appoint + -ee.

1680s, of objects, "to sink to the bottom," from Latin subsidere "sit down, settle, sink, fall; remain; crouch down, squat," from sub "under, beneath" (see sub-) + sidere "to settle," related to sedere "to sit," from PIE root *sed- (1) "to sit." Of liquid surfaces, "to sink to a lower level, be reduced" from 1706. Related: Subsided; subsiding.

1560s, "go into camp, settle in temporary quarters," from en- (1) "make, put in" + camp (n.). Related: Encamped; encamping.

1897, from matri- + local. Applied to the custom in certain social groups for a married couple to settle in the wife's home or community.

"one who sets or puts in order," especially "one who tries to settle a quarrel," mid-15c., Scottish, agent noun from redd (v.).

early 15c., appointement, "an agreement," also "a fixing of a date for official business," from Old French apointement, from apointer "arrange, settle, place" (see appoint). The meaning "act of placing in office" is attested from 1650s.

1650s, intransitive, "establish oneself in a place, settle, adopt a fixed residence," from Latin locatus, past participle of locare "to place, put, set, dispose, arrange," from locus "a place" (see locus).

Transitive sense of "to fix (something) in a place, settle or establish (something) in a particular spot" is from 1739, American English, originally of land surveys. And via the notion of "mark the limits of" (a parcel of land) the sense of the verb extended to "establish (something) in a place" (1807) and "find out the exact place of" (1882, American English). Related: Located; locating.

late 14c., from Anglo-French subsidie, Old French subside "help, aid, assistance, contribution," from Latin subsidium "a help, aid, assistance, (military) reinforcements, troops in reserve," from subsidere "to settle down, stay, remain" (see subside).

also re-adjust, 1742, "settle again, put in order again," from re- "back, again" + adjust. Later "adjust in a new way, make a new adjustment" (19c.). OED compares Medieval Latin readjustare. Related: Readjusted; readjusting; readjustment.