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v. Present participle of intercalate.

"This is how this system arrived at an agreement between the solar and the lunar periods: 8 solar years containing 2922 days, while 8 lunar years only contain 2832 days, there was a difference of 90 days, for which Cleostratus compensated by intercalating 3 months of 30 days each, which were placed after the third, fifth and eighth year of the cycle."

intercalated    intercalates    intercalating   

add   

bissextile year    bissextile    bissextile month   

intercalated    intercalating    intercalation    intercalary   

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