miscount (v.)

late 14c., "to count erroneously," also "to misjudge, deceive oneself," from Old French mesconter "give a false statement; miscalculate, be wrong in reckoning" (Modern French mécompter), from mes- "badly, wrongly" (see mis- (2)) + conter (see count (v.)). Related: Miscounted; miscounting.

"an erroneous counting or numbering," 1580s, from mis- (1) + count (n.2).