epact
‘the period of time necessary to bring the solar calendar into harmony with the lunar calendar’
Lexical development traced from the Tamil root:
F. épacte < La.Lat. epacta ‘an intercalary day’ < Gk. epakte < epaktos ‘brought in, imported, alien’ < epagein ‘to add, bring forward’ < epi ‘on’ + agein ‘put in motion, move; push forward, advance’ < ak < ag- < Tamil ukai