An ordinal number is a number that indicates position or order in relation to other numbers: *first, second, third*, and so on. Contrast with *cardinal number.*

*"*Ordinal numbers do not represent quantity," notes Mark Andrew Lim, "but rather indicate rank and position, such as the *fifth* car, the* twenty‐fourth* bar, the *second* highest marks, and so on" (*The Handbook of Technical Analysis*, 2012).

Ordinal numbers can be written as words (*second, third*) or as numerals followed by abbreviations (*2nd, 3rd*).

### Examples and Observations

- All ordinal numbers carry a suffix:
*-nd, -rd, -st,*or*-th*.

first (1st)

second (2nd)

third (3rd)

fourth (4th)

fifth (5th)

sixth (6th)

seventh (7th)

eighth (8th)

ninth (9th)

tenth (10th)

eleventh (11th)

twelfth (12th)

twentieth (20th)

twenty-first (21st)

twenty-second (22nd)

twenty-third (23rd)

twenty-fourth (24th)

thirtieth (30th)

one hundredth (100th)

one thousandth (1,000th)

one millionth (1,000,000th)

one billionth (1,000,000,000th)

### Using Ordinal Numbers and Cardinal Numbers Together

"When a cardinal number and an **ordinal number** modify the same noun, the ordinal number always precedes the cardinal number:

Thefirst twooperations were the most difficult to watch.

Thesecond threeinnings were quite dull.

In the first example, the ordinal number *first* precedes the cardinal number *two*. Both *first* and *two* are determiners. In the second example, the ordinal number *second* precedes the cardinal number *three*.

Both *second* and *three* are determiners. Try reading the sentences with the ordinal and cardinal numbers reversed. They simply sound wrong." (Michael Strumpf and Auriel Douglas, *The Grammar Bible*. Owl Books, 2004)

### More Tips on Using Ordinal Numbers

"Spell out **ordinal numbers**—*first, second, third, fourth*—except when quoting from another source.

In the interests of saving space they may also be expressed in numerals in notes and references. . . .

"Use words for ordinal numbers in names, and for numerical street names . . .:

theThirdReich, theFourthEstate, afifthcolumnist,SixthAvenue, aSeventh-Day Adventist

"Use figures for ages expressed in cardinal numbers, and words for ages expressed as ordinal numbers or decades:

a girl of 15, a 33-year-old man, between her teens and twenties, in his 33rd year"

(R. M. Ritter, *New Hart's Rules: The Handbook of Style for Writers and Editors*. Oxford University Press, 2005)

"Do not use the **ordinal** (*th, st, rd, nd*) form of numbers when writing the complete date: *January 15 is the date for the examination*. However, you may use the ordinal suffixes if you use only the day: *The 15th is the date for the examination.* . . .

"Write out ordinal numbers when they contain just one word: third prize, tenth in line, sixtieth anniversary, fifteenth birthday. Use numerals for the others: the 52nd state, the 21st Amendment." (Val Dumond, *Grammar for Grownups*. HarperCollins, 1993)