The Greek adverb/preposition exo (ἔξω) means outside, without, or forth. It appears over 60 times in the New Testament and carries significant theological freight as the marker of exclusion and mission. What is exo is outside the camp, outside the city walls, outside the covenant.
Hebrews 13:11–13 builds its entire theology of the cross on exo: Jesus suffered "outside the gate" (exo tes pyles), in the place of exclusion and shame, so that believers are called to "go forth to him outside the camp" (exo tes parembolou) bearing His reproach. The exo place — the margins, the excluded, the outsider — is precisely where the crucified Christ meets His people. Mission is always a movement toward the exo.