-some²

A group of a specified number.

Old English sum, some.

Examples are twosome, threesome, foursome, and eightsome, (in all of which the ending is pronounced /s@m/). Particularly in American English, the ending can be added to larger numbers to suggest ‘approximately’: twenty-some, forty-some, as in fifty-some people were there. In these cases, the suffix is said as though it were a separate word: /sVm/. See also ‑something.