horologer (n.)

late 14c., "clock-maker," via Latin from Greek horologe "clock, timepiece, instrument for measuring the hours of a day," from horologos "telling the hour," from hora "hour" (see hour) on model of astrologer, etc. Hence also obsolete English horologe "timepiece, sundial, hourglass, clock, cock" (late 14c.) and the old expression the devil in the horologe for "mischief in an orderly system" (17c.).