E-lēe'tro-ehŕŏn'o-grāph, n.

n. [Lat. electrum, Gr. ἤλεκτρον, and Eng. chronograph, q. v.] An instrument for accurately noting time, consisting of an electro-magnetic register connected with a clock, by means of which the seconds of the clock are spaced off in a series of marks on the moving surface of the register, and record-marks made in this series of second-marks of any observations at the instants they occur. It is used in astronomical observatories, to note transits and similar phenomena.