Strong's G1207 — δευτερόπρωτος (adjective)
deuteroprotos (dyoo-ter-op'-ro-tos) adj.
1. second-first
2. (specially) a designation of the Sabbath immediately after the Paschal week (being the second after Passover day, and the first of the seven Sabbaths intervening before Pentecost)
[from G1208 and G4413]
KJV: second ... after the first 
Root(s): G1208, G4413 
Hebrew root: πρῶτος