Definify.com
Webster 1913 Edition
Thirtieth
1.
Next in order after the twenty-ninth; the tenth after the twentieth; – the ordinal of thirty;
as, the
. thirtieth
day of the month2.
Constituting or being one of thirty equal parts into which anything is divided.
Thir′ti-eth
,Noun.
The quotient of a unit divided by thirty; one of thirty equal parts.
Webster 1828 Edition
Thirtieth
THIRTIETH
,Adj.