You searched for: “phonotelemeter”
phonotelemeter
A device consisting essentially of a stop watch, for estimating the distance of firearms in action by measuring the interval between the flash and the arrival of the sound waves from the discharges of the weapons.
This entry is located in the following units: meter-, metro-, metr-, -metrical, -metrically, -metron, -metric, -metrist, -meter, -meters, -metry, -metre (page 31) phon-, phono-, -phone, -phonia, -phonic, -phonetic, -phonous, -phonically, -phonetically, -phony + (page 16)