Abbott-Smith Manual Greek Lexicon
ἀδελφότης (G81)
2 **† ἀδελφότης , -ητος, ἡ ( ἀδελφός ), [in LXX: I Mac 12:10 , 17 , IV Mac 5 *;] abstract, brotherhood, brotherly affection (LXX). Concrete, the brotherhood , the Christian community: I Pe 2:17 5:9 (MM, VGT , s.v.).†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain