Lexical Definition

‎συμμέτοχος‎ symmétochos (soom-met'-okh-os) sharer ^G:A
from ‎σύν‎ and ‎μέτοχος‎

partaker.

• a co-participant

Abbott-Smith

* συν-μέτοχος (Rec. συμμ-), -ον,
partaking together with; as subst., ὁ σ., a joint partaker (c. dat. pers. et gen. rei, FlJ, BJ, i, 24, 6): c. gen. rei, Eph 3:6; c. gen. pers., ib. 5:7 (Arist.).†

Abbott-Smith References

Liddell-Scott-Jones

συμμέτοχος-οχος, ον,

partaking with another in a thing, τινί τινος [NT+1st c.AD+]: as substantive, joint owner, [Refs 6th c.AD+]

_{LSJ Scripture Refs: Eph.5.7}