Cis
/sɪs/noun
A prefix meaning “on this side of” or “same side of,” especially in chemistry and gender-related compounds.
Did you know?In Latin, cis was the opposite of trans, and that same ancient “this side / across” contrast survived into scientific language for centuries before entering modern social vocabulary.
Etymological Timeline
Proto-Indo-European
PIE
*kʷi- / *kʷis
“a demonstrative base meaning “this, here””
Latin
Latin
cis
“on this side of; this side of the boundary”
Classical Latin
Latin
citra
“on this side, this side of”
Late Medieval Latin
Latin
cis-
“a prefix meaning “on this side of” in learned compounds”
Modern English
English
cis
“a prefix or adjective meaning “on the same side of” or, in gender identity contexts, describing someone whose gender identity aligns with their sex assigned at birth”
Explore more surprising origins