Definition of addiment in English:

addiment

noun

  • 1rare Something that is added, an addition; an additive. rare.

  • 2historical Immunology
    Immunology = complement. Now chiefly historical.

Origin

Mid 17th century; earliest use found in Peter Heylyn (1599–1662), Church of England clergyman and historian. Apparently a shortening of additament.

Pronunciation:

addiment

/ˈadɪm(ə)nt/