Extensive

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late Middle English: from French extensif, -ive or late Latin extensivus, from extens- ‘stretched out’, from the verb extendere (see extend).

wiktionary

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From late Middle English, borrowed from Late Latin extensīvus, from Latin extensus.

etymonline

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extensive (adj.)

"vast, far-reaching;" c. 1600 of immaterial, c. 1700 of material things; from Late Latin extensivus, from extens-, past-participle stem of Latin extendere "to stretch out, spread" (see extend). Earlier in a medical sense, "characterized by swelling" (early 15c.). Related: Extensively; extensiveness.