ordinal number
B2Neutral to formal. Common in academic, technical, and everyday educational contexts; less frequent in casual conversation unless discussing sequences.
Definition
Meaning
A number indicating position or order in a sequence (e.g., 1st, 2nd, 3rd).
In linguistics, a numeral designating a position in an ordered sequence (e.g., 'first', 'second', 'third'). In mathematics, it can refer to a type of number used to describe the order type of a well-ordered set, generalising the notion of position to infinite sequences.
Linguistics
Semantic Notes
Contrasts directly with 'cardinal number' (e.g., one, two, three). The concept is fundamental for describing order, rankings, dates, fractions, and hierarchical lists.
Dialectal Variation
British vs American Usage
Differences
No significant lexical or syntactic differences. British English may more commonly use ordinal numbers for dates without 'the' and 'of' (e.g., '4th July' vs. US 'July 4th' or 'the fourth of July').
Connotations
Identical. Both varieties treat it as a standard, neutral mathematical/linguistic term.
Frequency
Equal frequency in educational and formal contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
[verb] + ordinal number + [noun] (e.g., 'Write the ordinal number for five.')[determiner] + ordinal number + [noun] (e.g., 'This is his third attempt.')Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “[None directly associated. The concept is technical.]”
Usage
Context Usage
Business
Used in reports for rankings (e.g., 'Q1 results placed us in the 2nd position').
Academic
Fundamental in mathematics, linguistics, statistics, and for referencing (e.g., 'see the 3rd chapter').
Everyday
Used for dates, birthdays, floors in buildings, competition results (e.g., 'She finished in first place').
Technical
In set theory, referring to transfinite ordinals; in computing, for indexing array elements.
Examples
By Part of Speech
verb
British English
- [No standard verb form]
American English
- [No standard verb form]
adverb
British English
- [Not standard]
American English
- [Not standard]
adjective
British English
- The ordinal position is critical.
- We need the ordinal data for the chart.
American English
- The ordinal ranking is now final.
- She studies ordinal measurement scales.
Examples
By CEFR Level
- 'First' and 'second' are ordinal numbers.
- My birthday is on the 23rd of June.
- In the list, please write the ordinal number next to each item.
- He came in third in the race.
- The survey data required conversion from cardinal to ordinal numbers for statistical analysis.
- The monarch's regnal number is an ordinal, like Elizabeth the Second.
- The theory of transfinite ordinal numbers extends the concept of ordering beyond the finite.
- Linguists have analysed the morphological derivation of ordinal numbers from their cardinal counterparts.
Learning
Memory Aids
Mnemonic
Think 'ORDERinal' – ordinal numbers show ORDER (1st, 2nd, 3rd).
Conceptual Metaphor
SEQUENCE IS A LINE (positions are points on that line). HIERARCHY IS A LADDER (ordinals define the rungs).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Russian often omits the word 'number' in this phrase, saying just 'порядковое' (ordinal). English requires the full noun phrase 'ordinal number' or just 'ordinal'.
- In dates, Russian uses cardinal numbers in the genitive case (e.g., 'пятое мая' literally 'fifth of May'), while English uses the ordinal form ('the fifth of May' or 'May fifth').
Common Mistakes
- Using a cardinal number where an ordinal is required (e.g., 'I live on floor three' instead of 'the third floor').
- Incorrectly forming the ordinal suffix (e.g., '21th' instead of '21st').
- Mispronouncing 'ordinal' as /ɔːrˈdaɪ.nəl/ instead of /ˈɔːr.dən.əl/.
Practice
Quiz
What is the key function of an ordinal number?
FAQ
Frequently Asked Questions
In most contexts, yes. 'Ordinal' is commonly used as a shorthand for 'ordinal number' among mathematicians, linguists, and teachers.
There is no universally agreed ordinal for zero in common usage. In technical contexts like set theory, 'zeroth' is sometimes used, but sequences typically start from 'first'.
Generally, add '-th' to the cardinal number (fourth, sixth). Exceptions: first, second, third, and numbers ending in 1, 2, or 3 (except 11, 12, 13) use -st, -nd, -rd respectively (21st, 32nd, 103rd).
They are essential for giving dates, directions (turning on the 2nd street), understanding rankings, listing items in order, and discussing sequences in both everyday and professional life.