adjective

1. having or consisting of many parts, elements, etc.; more than one or once; manifold or complex
2. shared by or involving many
3. many or very many; numerous
4. Elec. designating or of a circuit having two or more conductors connected in parallel

Etymology: Fr < L multiplex < multi-, multi- + -plex, -fold: see duplex

noun

1. Elec. a group of terminals so arranged that connection with the circuit can be made at any of a number of points
2. Math. a number which is a product of some specified number and another number 10 is a multiple of 5