ADDIT'AMENT, noun [Latin additamentum, from additus and ment. See Add.] An addition, or rather the thing added, as furniture in a house; any material mixed with the principal ingredient in a compound. Ancient anatomists gave the name to an epiphysis, or junction of bones without articulation. [Little used in either sense.]
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI