Etymograph

English

simplex

Simplex comes from Latin simplex ‘plain, simple’, and goes back to Proto-Indo-European *sm̥- ‘one’.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*sm̥-1‘one’reconstructed
  2. Latinc. 75 BCE–200 CEsimplex2‘plain, simple’
  3. Englishearliest quotation 1978simplex2

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Latin simplex
  2. 2 Wiktionary, English simplex
  3. Earliest quotation in Wiktionary’s entry: 1978, Helga Harries-Delisle, Contrastive Emphasis and Cleft Sentences: “The question is: is 139. [“Priexal Vanja. ‘arrived Vanya’”]…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*sm̥-Wiktionary, Latin simplex‘one’reconstructed
  2. Latinc. 75 BCE–200 CEsimplexWiktionary, English simplex‘plain, simple’
  3. Englishearliest quotation 1978simplexWiktionary, English simplex. Earliest quotation in Wiktionary’s entry: 1978, Helga Harries-Delisle, Contrastive Emphasis and Cleft Sentences: “The question is: is 139. [“Priexal Vanja. ‘arrived Vanya’”]…”

The story

The adjective is a learned borrowing from Latin simplex (‘plain, simple; single’). The first part, sim-, comes from Proto-Indo-European *sem-, *sm̥- (‘one; together’). The second part, -plex, may be from *pleḱ- (‘to weave’). Noun sense 1 (‘generalization of a triangle or tetrahedron to an arbitrary dimension’) was apparently coined by the Dutch mathematician Pieter Hendrik Schoute (1846–1913) as a short version of Simplicissimum in Mehrdimensionale Geometrie (in German, 1902). (In his pioneering works on algebraic topology, the French mathematician Henri Poincaré (1854–1912) had previously introduced the concept, but not the actual term simplex.)

Full etymology on Wiktionary

Every English word from Proto-Indo-European *sm̥-

Today it means

adj Having a single structure; not composite or complex; undivided, unitary.

Sources

Sources: Wiktionary, “simplex”; the older steps come from the Wiktionary entry for Latin simplex. 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 *sm̥- / simplex

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