exo-

prefix

Etymology: Etymology tree Proto-Indo-European *h₁éǵʰ Proto-Indo-European *-s Proto-Indo-European *h₁eǵʰs Proto-Hellenic *eks Ancient Greek ἐκ (ek) Ancient Greek ἔξω (éxō)der. English exo- From Ancient Greek ἔξω (éxō, “outer; external”).

1. outside; external
2. outside; external

   “exo- + planet → exoplanet”

   “exo- + biology → exobiology”