parardha

dvi-parārdha-ākhyaḥ measured by the two halves of Brahmā's life; SB 3.11.38
dvi-parārdha two superdurations of time; SB 3.11.39
dvi-parārdha two parārdhas; SB 3.32.8
dvi-parārdha the duration of the life of Brahmā; SB 5.14.29
dvi-parārdha-saṃjñe the time known as the end of a dvi-parārdha; SB 9.4.53-54
dvi-parārdha-avasāne after millions and millions of years (the life of Brahmā); SB 10.3.25
dvi-parārdha two parārdhas, totalling 311,040,000,000,000 years; SB 11.10.30
dvi-parārdha the entire duration of the universe; SB 12.8.43