The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
Appendix I
Indo-European Roots
ENTRY:
sed-
DEFINITION:
To sit. Derivatives include sit, soot, séance, siege, obsess, subside, soil1, and chair. I. Basic form *sed-.1. Suffixed form *sed-yo-.a.sit, from Old English sittan, to sit; b.sitz bath, sitzmark, from Old High German sizzen, to sit. Both a and b from Germanic *sitjan.2. Suffixed form *sed-lo-, seat. settle, from Old English setl, seat, from Germanic *setlaz.3. Suffixed (stative) form *sed--.séance, sedentary, sederunt, sedile, sediment, sessile, session, sewer2, siege; assess, assiduous, assize, dissident, insessorial, insidious, obsess, possess, preside, reside, subsidy, supersede, surcease, from Latin sedre, to sit. 4. Suffixed form *sed-r-.hedron; cathedra, cathedral, chair, ephedrine, exedra, Sanhedrin, tetrahedron, from Greek hedr, seat, chair, face of a geometric solid. 5. Prefixed and suffixed form *pi-sed-yo-, to sit upon (*pi, on; see epi). piezo-; isopiestic, from Greek piezein, to press tight. 6. Basic form *sed-.a.edaphic, from Greek edaphos, ground, foundation (with Greek suffix -aphos); b.Upanishad, from Sanskrit upaniad, Upanishad, from -sad, sitting; c.tanist, from Old Irish tnaise, designated successor, from Celtic *tnihessio-, one who is waited for, from *to-ad-ni-sed-tio, from *to-ad-ni-sed-, to wait for (*ad-, to; see ad-). 7. Suffixed form *sed-o-, sitting. eisteddfod, from Welsh eistedd, sitting, from Celtic *eks-d-sedo- (*eks-, out, and *d-, out, from; see eghs and de-). II. O-grade form *sod-.1. Perhaps suffixed form *sod-dhlo-.saddle, from Old English sadol, saddle, from Germanic *sadulaz, seat, saddle. 2. Suffixed (causative) form *sod-eyo-.a.set1, from Old English settan, to place; b.beset, from Old English besettan, to set near; c.ersatz, from Old High German irsezzan, to replace, from sezzan, to set. ac all from Germanic *(bi-)satjan, to cause to sit, set. 3. Suffixed form *sod-yo-.soil1, from Latin solium, throne, seat. III. Zero-grade form *-sd- (in compounds), assimilated to *-zd-.1. Reduplicated form *si-sd- becoming *si-zd-.a.subside, from Latin sdere, to sit down, settle; b.synizesis, from Greek hizein, to sit down, settle down. 2. Compound suffixed form *ni-zd-o-, nest, literally (bird's place of) sitting down (*ni-, down). a.nest, from Old English nest, from Germanic *nistaz;b.niche, nick, nide, nidus; eyas, nidicolous, nidifugous, nidify, from Latin ndus. nest. 3. Compound suffixed form *kuzdho-zd- (see (s)keu-). IV. Lengthened-grade form *sd-.1. see2, from Latin sds, seat, residence. 2. Suffixed form *sd-i-, settler. cosset, possibly from Old English -sta, -ste, inhabitant(s), from Germanic *stn-, *sti-.3. Suffixed form *sd-yo-.seat, from Old Norse sæti, seat, from Germanic *(ge)stjam, seat (*ge-,*ga-, collective prefix; see kom). 4. Suffixed form *sd--.sedate1, from Latin sdre, to settle, calm down. 5. Suffixed form *sd-es-, seat. banshee, from Old Irish síd, fairy mound. V. Lengthened o-grade form *sd-.soot, from Old English st, soot (< that which settles), from Germanic *stam, from suffixed form *sd-o-. (Pokorny sed- 884.)