Twentieth \Twen"ti*eth\, a. [From Twenty; cf. AS. twentigo?a. See Twenty.]

1. Next in order after the nineteenth; tenth after the tenth; coming after nineteen others; -- the ordinal of twenty.

2. Consisting, or being, one of twenty equal parts into which anything is divided.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Twentieth \Twen"ti*eth\, n.

1. The next in order after the nineteen; one coming after nineteen others.

2. The quotient of a unit divided by twenty; one of twenty equal parts of one whole.

Source: Webster's Revised Unabridged Dictionary (1913)