Osis

OSIS or variant may refer to:


 * OSIS
 * Open Source Information System
 * Open Scripture Information Standard
 * Organisasi Siswa Intra Sekolah, Indonesian for Intra-school students organization

The suffix -osis is used for forming a number of medical terms. The suffix itself signifies only a general functional disorder, but the constructed words are more specific. It is often used to denote a biological process (i.e. Apoptosis, Phagocytosis, Necrosis...)
 * -osis

Osis (feminine: Ose), is a Latvian language surname meaning "ash" (tree; Fraxinus excelsior)
 * Osis
 * Guntis Osis (born 1962), Soviet Latvian bobsledder
 * Karlis Osis (1917–1997), paranormal researcher