- a combining form meaning “half,” used in the formation of compound words: hemimorphic.
- halfhemicycle; hemisphere Compare demi- (def. 1), semi- (def. 1)
word-forming element meaning “half,” from Greek hemi- “half,” from PIE root *semi-, which is the source of Sanskrit sami, Latin semi- (see semi-), Old High German sami- “half,” and Old English sam-, denoting a partial or imperfect condition (see sandblind).
- A prefix meaning half, as in hemisphere, half a sphere.