-ment Look up -ment at Dictionary.com
suffix forming nouns, originally from French and representing Latin -mentum, which was added to verb stems sometimes to represent the result or product of the action. French inserts an -e- between the verbal root and the suffix (as in commenc-e-ment from commenc-er; with verbs in ir, -i- is inserted instead (as in sent-i-ment from sentir). Used with English verb stems from 16c. (as in merriment, which also illustrates the habit of turning -y to -i- before this suffix).