English
obsession
Obsession comes from Latin obsessio ‘a besieging’, from sedeō ‘to sit’, and ultimately from Proto-Indo-European *sed-.
- Proto-Indo-Europeanc. 4500–2500 BCE*sed-1‘to sit’reconstructed
- Proto-Indo-Europeanc. 4500–2500 BCE*sedéh₁yeti1reconstructed
- Proto-Italicc. 1500–700 BCE*sedēō1‘to sit, to be sitting, to be seated’reconstructed
- Latinc. 75 BCE–200 CEsedeō1‘to sit’
- Latinc. 75 BCE–200 CEobsideō2as obsidere‘to besiege’
- Latinc. 75 BCE–200 CEobsessio2‘a besieging’
- Englishearliest quotation 1973obsession2
attested reconstructed ? uncertain or disputed deepest recorded ancestor
- 1 Wiktionary, Latin obsideo
- 2 Wiktionary, English obsession
- Earliest quotation in Wiktionary’s entry: 1973, Jessie Penn-Lewis, Evan Roberts: “if an evil spirit counterfeits the presence of God,…”.
Lineage
- Proto-Indo-Europeanc. 4500–2500 BCE*sed-Wiktionary, Latin obsideo‘to sit’reconstructed
- Proto-Indo-Europeanc. 4500–2500 BCE*sedéh₁yetiWiktionary, Latin obsideoreconstructed
- Proto-Italicc. 1500–700 BCE*sedēōWiktionary, Latin obsideo‘to sit, to be sitting, to be seated’reconstructed
- Latinc. 75 BCE–200 CEsedeōWiktionary, Latin obsideo‘to sit’
- Latinc. 75 BCE–200 CEobsideōWiktionary, English obsessionas obsidere‘to besiege’
- Latinc. 75 BCE–200 CEobsessioWiktionary, English obsession‘a besieging’
- Englishearliest quotation 1973obsessionWiktionary, English obsession. Earliest quotation in Wiktionary’s entry: 1973, Jessie Penn-Lewis, Evan Roberts: “if an evil spirit counterfeits the presence of God,…”
Formed from obsess + -ion
Proto-Indo-European *sed- ‘to sit’
…
Proto-Italic *sedēō ‘to sit, to be sitting, to be seated’
Latin sedeō ‘to sit’
Latin obsideō ‘sit on or in, remain, besiege’
Latin obsessus ‘besieged, blockaded’
English obsess
Linked words
through Proto-Indo-European *sed- ‘to sit’
set, method, sell, chair, sitting, sit, seat, settle, nest, niche, saddle, exodus, possess, nye, subsidy, prasad, cathode, soot, anode, setter, beset, sate, chaise, ersatz, salo, nidal, nias, besiege, polyhedron, 82 more
through Proto-Italic *sedēō ‘to sit, to be sitting, to be seated’
assessor, presidente, assize, 25 more
through Latin sedeō ‘to sit’
president, size, resident, siege, possession, assess, sedan, reside, sediment, residual, residue, sedentary, insidious, sedative, dissident, sedate, possessive, seance, presidio, presidium, sessile, 27 more
Today it means
noun The quality of being obsessed; an unshakeable feeling that one topic or activity must be pursued above other interests.
Sources
Sources: Wiktionary, “obsession”; the older steps come from the Wiktionary entry for Latin obsideo. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.
Etymograph / Proto-Indo-European *sed- / obsession