Therblig,

Definition of Therblig:

1. Base elemental motion (into which any job can be broken down) in a time-and-motion study, representing one of the 18 motions standardized by the husband and wife team of US industrial engineering pioneers Frank Gilbreth (1868-1924) and Dr. Lillian Gilbreth (1878-1972). Therblig is Gilbreth spelled backwards (except th).