We wish to propose that the word “receptance” should be used instead of “admittance” as applied to mechanical systems (see R. and M. 2,000, 1947). By this, we mean that if a generalised disturbing force Fse iωt is applied at the s th generalised co-ordinate q s of a linear oscillatory system, then the response at the r th generalised co-ordinate is given by

q s = αrs Fse iωt

where αrs is the “Cross-receptance” between q r and q s. If r = s, then αrs would be the “direct receptance” at q s.