The Greek verb diploo means to double or repay in double measure. It appears in Revelation 18:6 in the context of divine judgment on Babylon.
Diploo appears in the great judgment pronouncement of Revelation 18:6: 'Give back to her as she has given; pay her back double for what she has done; pour her a double portion from her own cup.' This is the principle of lex talionis (eye for an eye) applied to final judgment — the measure of punishment corresponds to the measure of wickedness. But it also echoes the Old Covenant provisions for double restitution (Exodus 22:4). God's justice is never arbitrary; it is proportional, perfect, and final. The inverse is also true — God's blessings on His people can come in double measure (Isaiah 61:7).