s. three,
tirayangkam ,tiriyangkam , the three members of a calendar.
tirayotaci , the 13th day of each lunar fortnight.
tiraracikam , rule of three.
s. three,
திரயாங்கம் ,திரியாங்கம் , the three members of a calendar.
திரயோதசி , the 13th day of each lunar fortnight.
திரராசிகம் , rule of three.