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).
hemi- in Medicine
hemi-pref. Half: hemicardia.
hemi- in Science
hemi- A prefix meaning "half," as in hemisphere, half a sphere.