Vine's Expository Dictionary: View Entry
πέμπτος pémptos, pemp'-tos; from G4002; fifth:—fifth.
The KJV translates Strong's G3991 in the following manner: fifth (4x).
fifth
Strong's Number G3991 matches the Greek πέμπτος (pemptos), which occurs 4 times in 4 verses in the TR Greek.
View OT results in the LXX Greek concordance
View NT results in the MGNT Greek concordance
Rev 6:9
Rev 9:1
Rev 16:10
Rev 21:20