From koinos; a sharer, i.e. Associate -- companion, X fellowship, partaker, partner.
see GREEK koinos
a. a partner, associate, comrade, companion: 2 Corinthians 8:23; ἔχειν τινα κοινωνόν, Philemon 1:17; εἰμί κοινωνός τίνι, to be one's partner, Luke 5:10; τίνος (the genitive of person), to be the partner of one doing something, Hebrews 10:33; τίνος ἐν τῷ αἵματι, to be one's partner in shedding the blood etc. Matthew 23:30.
b. a partaker, sharer, in any thing; with the genitive of the thing: τῶν παθημάτων, 2 Corinthians 1:7; τῆς δόξης, 1 Peter 5:1; θείας φύσεως, 2 Peter 1:4; τοῦ θυσιαστηρίου, of the altar (at Jerusalem) on which sacrifices are offered, i. e. sharing in the worship of the Jews, 1 Corinthians 10:18; τῶν δαιμονίων, partakers of (or with) demons, i. e. brought into fellowship with them, because they are the authors of the heathen worship, ibid. 20; (ἐν τῷ ἀφθάρτῳ κοινωνοί ... ἐν τοῖς φθαρτοῖς, joint partakers in that which is imperishable ... in the blessings which perish, Epistle of Barnabas 19, 8 [ET]; see κοινωνέω, at the end).