In linguistics, ordinal numbers are words representing position or rank in a sequential order. The order may be of size, importance, chronology, and so on. In English, they are adjectives such as 'third' and 'tertiary'.
Ordinal numbers may be written in English with numerals and letter suffixes: 1st, 2nd or 2d, 3rd or 3d, 4th, 11th, 21st, 101st, 477th, etc. In some countries, written dates omit the suffix, although it is nevertheless pronounced. For example: 5 November 1605 (pronounced "the fifth of November ... "); November 5, 1605, ("November Fifth ..."). When written out in full with "of", however, the suffix is retained: the 5th of November. In other languages, different ordinal indicators are used to write ordinal numbers.
In American Sign Language, the ordinal numbers first through ninth are formed with handshapes similar to those for the corresponding cardinal numbers with the addition of a small twist of the wrist.
In English, the main ordinal series is 'first', 'second', .... It is used in a variety of rankings, including time ('the first president of France'), space ('the first left'), and quality ('first class cabin').