primogenitor
‘a firstborn child, the fact or condition of being the firstborn child and its right; the earlier ancestor’
Lexical development traced from the Tamil root:
M.Lat. primogenitor < Lat. primo ‘first in order of time; at first’ < primus ‘first’ + genitor ‘father’ < genitus < gignere ‘to beget’ < jen < gene- < Tamil īṉ