Webster's Revised Unabridged Dictionary · 1913

Seventeenth

Seventeenth , adjective

[From Seventeen: compare Anglo-Saxon seofonteóea, seofonteogeea.]

1.
Next in order after the sixteenth; coming after sixteen others.
In... the seventeenth day of the month... were all the fountains of the great deep broken up. — Gen. vii. 11
2.
Constituting or being one of seventeen equal parts into which anything is divided.

Seventeenth , noun

1.
The next in order after the sixteenth; one coming after sixteen others.
2.
The quotient of a unit divided by seventeen; one of seventeen equal parts or divisions of one whole.
3.
(Music) An interval of two octaves and a third.