sed-
“to sit, to be seated”sit, settle, seat
Root for sitting, yielding Latin sedere, English sit, set, settle, seat, saddle.
Discussion
The Proto-Indo-European root *sed- meant "to sit," and few roots have generated a richer family of descendants. Pokorny (IEW 884–887) devoted extensive treatment to this root, documenting its reflexes in every major branch. Latin sedēre "to sit" is the direct continuation, yielding English session, sediment, sedentary, preside and president (one who sits before), reside and resident, obsess (originally "to sit before, to besiege"), and assess (to sit beside as a judge's assistant). The Latin prefixed form obsidēre gave siege through Old French, while subsīdium "reserve troops" produced subsidy. Greek hédra "seat, base" connects to the root, whence cathedral — originally kathédra, "a sitting down," the bishop's chair that named the church. The Germanic branch shows English sit (Old English sittan), set (the causative), seat, and settle. Watkins traces nest to *ni-sd-o- "a sitting-down place." Sanskrit sad- (sīdati, "he sits") confirms the Indo-Iranian development. The metaphorical extensions are culturally revealing: from physical sitting arose the concepts of besieging (obsess, siege), presiding (president), and residing (sedentary), mapping the journey from a body's posture to the abstractions of authority, persistence, and place.
Notes
Pokorny 884-887. English sit, set, saddle, nest, chair (via Latin cathedra).
Related Roots
English Words from *sed-
These modern English words descend from this root. Each page traces the full journey from PIE to present-day English.