a. [ L. nutriens, p. pr. of nutrire. See Nourish. ] Nutritious; nourishing; promoting growth. [ 1913 Webster ]
n. n. 1. Any substance which has nutritious qualities, i. e., which nourishes or promotes growth; a nutriment. [ 1913 Webster ]
2. Specifically: (Microbiology) A substance added to the growth medium of a microorganism to promote growth. [ PJC ]