-ham

Etymology

From the convergence of two elements:

Middle English -ham, -hame, from Old English hām (“home, farm, estate”), from Proto-West Germanic *haim. Cognate with German -heim and Dutch -hem, and doublet of home.
Middle English -hamme, from Old English hamm (“enclosure”, often specifically “land enclosed by a river”), from the root of Proto-West Germanic *hammjan (“to pinch, to hem, to enclose”).

Pronunciation

(UK) IPA^(key): (always unstressed) /əm/, /həm/
Audio (UK): (file)
(US) IPA^(key): (with secondary stress) /ˌhæm/, (unstressed) /həm/, /əm/

This suffix often triggers a spelling pronunciation, especially after -t, as in town names like Grantham. When this happens, the /h/ in -ham is no longer pronounced.