purchase: [13] To purchase something is etymologically to ‘hunt it down’. It comes from Old French pourchacier ‘pursue’, hence ‘try to obtain’, a compound verb formed from the intensive prefix pour- and chacier ‘pursue’ (source of English chase). It arrived in English meaning ‘obtain’. This sense had virtually died out by the end of the 17th century, but not before it had evolved in the 14th century to ‘buy’. => chase
