TACH' The term 'TACH SITE' is composed of two words, 'TACH' and 'SITE'. The word 'TACH' is a four-letter word meaning 'a device for measuring the speed of a rotating shaft or disk'. The word 'SITE' is a four-letter word meaning 'a place where something is located or has been established'. Together, the term 'TACH SITE' refers to a place where a device for measuring the speed of a rotating shaft or disk is located.