Strong's G4821 — συμβασιλεύω (verb)
sumbasileuo (soom-bas-il-yoo'-o) v.
1. to be co-regent (figuratively)
[from G4862 and G936]
KJV: reign with 
Root(s): G4862, G936 
Hebrew root: βασιλεύω
Occurrences: 2