dissection (n.)

1580s, "operation of cutting open or separating into parts," from Middle French dissection (16c.) or directly from Medieval Latin dissectionem (nominative dissectio), noun of action from past-participle stem of Latin dissecare "cut in pieces," from dis- "apart" (see dis-) + secare "to cut" (from PIE root *sek- "to cut"). Meaning "process of cutting open an animal or plant for examination of organs and tissues" is from c. 1600. Transferred sense of "act of separating anything into distinct parts for critical examination" is from 1640s.