(Canada, historical) Thirteenth grade.

The ordinal form of the number thirteen.

The person or thing in the thirteenth position. / One of thirteen equal parts of a whole. / (music) The interval comprising an octave and a sixth. / (in dates) The thirteenth day of a month.

plural of thirteenth

A particular date combination that occurs when the thirteenth day of a month falls on a Friday, and which is considered unlucky in some cultures.

In the thirteenth place; thirteenth in a row.

The monetary amount of thirteen pence.

Having a value or cost of thirteenpence.

(informal) Of about thirteen years of age.

By a factor of thirteen, tredecuple.