Definitions

1. adjective

being or pertaining to the ordinal number 19

“She was the nineteenth student to arrive at the conference.”

2. noun

a person or thing in the nineteenth position in a series or sequence

“The nineteenth player was eliminated from the tournament.”

3. numeral

the ordinal number 19

“The nineteenth century saw significant social change.”

4. adverb

in the position of nineteenth in a series or sequence

“The new employee was assigned the nineteenth task.”