Commonly referred to PIE root *tem- "to cut," on notion of "place reserved or cut out" [Watkins], or to root *temp- "to stretch" [Klein, de Vaan], on notion of "cleared (measured) space in front of an altar" (from PIE root *ten- "to stretch;" compare temple (n.2)), the notion being perhaps the "stretched" string that marks off the ground. Compare Greek temenos "sacred area around a temple," literally "place cut off," from stem of temnein "to cut." Figurative sense of "any place regarded as occupied by divine presence" was in Old English. Applied to Jewish synagogues from 1590s.
A similar notion seems to be at work in Old English ðunwange, Old Norse þunn-vangi, Old High German dunwangi "temple," literally "thin cheek." The less-likely guess is that it is associated with tempus span "timely space" (for a mortal blow with a sword).
1590s, "reflect upon, ponder, study, view mentally, meditate," from Latin contemplatus, past participle of contemplari "to gaze attentively, observe; consider, contemplate," originally "to mark out a space for observation" (as an augur does), from assimilated form of com-, here perhaps an intensive prefix (see com-), + templum "area for the taking of auguries" (see temple (n.1)).
From c. 1600 as "to view or observe with continued attention." From 1816 as "to intend, have in view as a future act." Related: Contemplated; contemplating.
The meaning "pattern or gauge for shaping a piece of work" is first recorded 1819 in this form, earlier temple (1680s); the form was altered mid-19c., probably influenced by plate [Barnhart], but the pronunciation did not begin to shift until more recently (templet is still the primary entry for the word in Century Dictionary).
c. 1200, contemplacioun, "religious musing," from Old French contemplation and directly from Latin contemplationem (nominative contemplatio) "act of looking at," noun of action from past-participle stem of contemplari "to gaze attentively, observe; consider, contemplate," originally "to mark out a space for observation" (as an augur does), from assimilated form of com-, here perhaps an intensive prefix (see com-), + templum "area for the taking of auguries" (see temple (n.1)).
From late 14c. as "reflection, thinking, thought, act of holding an idea continuously before the mind." Meaning "act of looking attentively at anything" is from late 15c.
It forms all or part of: anatomy; atom; contemplate; contemplation; diatom; dichotomy; -ectomy; entomolite; entomology; entomophagous; epitome; phlebotomy; temple (n.1) "building for worship;" tmesis; tome; -tomy; tonsorial; tonsure.
It is the hypothetical source of/evidence for its existence is provided by: Greek temnein "to cut," tomos "volume, section of a book," originally "a section, piece cut off;" Old Church Slavonic tina "to cleave, split;" Middle Irish tamnaim "I cut off," Welsh tam "morsel."
It forms all or part of: abstain; abstention; abstinence; abstinent; atelectasis; attend; attenuate; attenuation; baritone; catatonia; catatonic; contain; contend; continue; detain; detente; detention; diatonic; distend; entertain; extend; extenuate; hypotenuse; hypotonia; intend; intone (v.1) "to sing, chant;" isotonic; lieutenant; locum-tenens; maintain; monotony; neoteny; obtain; ostensible; peritoneum; pertain; pertinacious; portend; pretend; rein; retain; retinue; sitar; subtend; sustain; tantra; telangiectasia; temple (n.1) "building for worship;" temple (n.2) "flattened area on either side of the forehead;" temporal; tenable; tenacious; tenacity; tenant; tend (v.1) "to incline, to move in a certain direction;" tendency; tender (adj.) "soft, easily injured;" tender (v.) "to offer formally;" tendon; tendril; tenement; tenesmus; tenet; tennis; tenon; tenor; tense (adj.) "stretched tight;" tensile; tension; tensor; tent (n.) "portable shelter;" tenterhooks; tenuous; tenure; tetanus; thin; tone; tonic.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit tantram "loom," tanoti "stretches, lasts," tanuh "thin," literally "stretched out;" Persian tar "string;" Lithuanian tankus "compact," i.e. "tightened;" Greek teinein "to stretch," tasis "a stretching, tension," tenos "sinew," tetanos "stiff, rigid," tonos "string," hence "sound, pitch;" Latin tenere "to hold, grasp, keep, have possession, maintain," tendere "to stretch," tenuis "thin, rare, fine;" Old Church Slavonic tento "cord;" Old English þynne "thin."