The meaning of the word communion itself is that of a “common” “union” shared between two or more members. Thus this word is used in a diversity of ways, one of them in relation to the Eucharist celebration of taking “communion.” In this sense, taking communion is a liturgical enactment of the covenant where a common union is formed between two or more members making them one. Another use of the word communion is ecclesiastical, to distinguish the Church as a communion from the Church as a denomination. Denominations define themselves by what they hold in distinction from others while a communion emphasizes what it has in common with all expressions of the Church. It this sense, Basileia is a communion, not a denomination.
Also see Convergence, and Eucharistic Worship.