early 15c., "action of entangling," from Latin implicationem (nominative implicatio) "an interweaving, an entanglement," noun of state from past participle stem of implicare "involve, entangle; embrace; connect closely, associate," from assimilated form of in- "into, in, on, upon" (from PIE root *en "in") + plicare "to fold" (from PIE root *plek- "to plait"). Meaning "that which is implied (but not expressed), inference drawn from what is observed" is from 1550s.
