Sem"i- (?). [L. semi; akin to Gr. , Skr. sami-, AS. sam-, and prob. to E. same, from the division into two parts of the same size. Cf. Hemi-, Sandelend.]
A prefix signifying half, and sometimes partly or imperfectly; as, semiannual, half yearly; semitransparent, imperfectly transparent.
⇒ The prefix semi is joined to another word either with the hyphen or without it. In this book the hyphen is omitted except before a capital letter; as, semiacid, semiaquatic, semi-Arian, semiaxis, semicalcareous.
© Webster 1913.