extensive (adj.)youdaoicibaDictYouDict[extensive 词源字典]
"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.[extensive etymology, extensive origin, 英语词源]