Compound nouns & dates
Two-word nouns; saying the date.
A compound noun is a noun made from two words put together. The two parts can be written as one word (toothbrush, classroom, football), as two separate words (bus stop, post office, swimming pool), or sometimes with a hyphen (check-in). The first word tells us what kind or what it is used for, and the second word is the main noun: 'tooth' + 'brush' = a brush for teeth. When we talk about dates, we use ordinal numbers: 1st (first), 2nd (second), 3rd (third), 4th (fourth), and so on. We say the ordinal number, then 'of', then the month: 'the fifth of June'. We can also say the month first: 'June the fifth' or write it as 'June 5th'. For years before 2000, we say them in two pairs of digits: 1999 = 'nineteen ninety-nine'. For 2000–2009 we usually say 'two thousand and…': 2005 = 'two thousand and five'. From 2010 the two-pair form is normal again: 2024 = 'twenty twenty-four'. Always use 'the' before the ordinal number when speaking. For example: My birthday is on the third of October, and I keep my diary in my bookcase next to the window.
Key terms
| Cardinal (number) | Ordinal (spoken) | Abbreviation | Special note |
|---|---|---|---|
| 1 | first | 1st | Irregular — learn it |
| 2 | second | 2nd | Irregular — learn it |
| 3 | third | 3rd | Irregular — learn it |
| 4 | fourth | 4th | Regular: + th |
| 5 | fifth | 5th | Spelling change: five → fifth |
| 8 | eighth | 8th | No extra 't': eight → eighth |
| 9 | ninth | 9th | Drop 'e': nine → ninth |
| 11 | eleventh | 11th | Regular: + th |
| 12 | twelfth | 12th | Spelling change: twelve → twelfth |
| 20 | twentieth | 20th | y → ieth: twenty → twentieth |
| 21 | twenty-first | 21st | Combine: twenty + first |
| 31 | thirty-first | 31st | Combine: thirty + first |
The first three ordinals (1st, 2nd, 3rd) are irregular. All others add -th, sometimes with a spelling change.
| Pattern | Example written | Example spoken |
|---|---|---|
| the + ordinal + of + month | 5 May / May 5th | the fifth of May |
| month + the + ordinal | May 5th | May the fifth |
| the + ordinal + of + month + year (pre-2000) | 12 August 1998 | the twelfth of August, nineteen ninety-eight |
| the + ordinal + of + month + year (2000–2009) | 2 September 2005 | the second of September, two thousand and five |
| the + ordinal + of + month + year (2010+) | 2 September 2024 | the second of September, twenty twenty-four |
Always use 'the' before the ordinal number when speaking a date. Never use a cardinal number (e.g. 'five of May' is wrong).
| Pattern | Example | Meaning |
|---|---|---|
| One word | toothbrush | a brush for your teeth |
| One word | football | a ball game played with feet |
| One word | classroom | a room for lessons |
| One word | backpack | a pack worn on your back |
| One word | sunglasses | glasses that protect from the sun |
| One word | firefighter | a person who fights fires |
| Two words | bus stop | a place where buses stop |
| Two words | post office | an office that handles post (mail) |
| Two words | swimming pool | a pool for swimming |
| Two words | birthday cake | a cake for a birthday |
| Hyphenated | check-in | the process of registering on arrival |
There is no single rule for one word vs two words vs hyphen — you need to learn each compound noun as a whole.
- 1Step 1: Find the ordinal number for 21: 21 → twenty-first (NOT 'twenty-one', which is a cardinal number)
- 2Step 2: Add 'the' before the ordinal: the twenty-first
- 3Step 3: Add 'of' and the month name: the twenty-first of October
- 4Step 4 (optional): Add the year: the twenty-first of October, twenty twenty-four (for 2024, say it as two pairs)
- 5Result: Spoken: 'the twenty-first of October' — Written short form: 'October 21st'
- 1Step 1: Identify the two words: 'sun' + 'glasses' — two separate words
- 2Step 2: Decide: which word describes the other?: 'sun' describes 'glasses' (they protect you from the sun) → 'sun' comes FIRST
- 3Step 3: Write as one word (check a dictionary if unsure): sunglasses (one word, no apostrophe, no space)
- 4Note on word order: The describing word always comes BEFORE the main noun: 'car key' (a key for a car), NOT 'key car'.
Do NOT use a cardinal number in a date. A very common mistake is 'the twenty-one of October' — the correct form is 'the twenty-first of October'. Dates always need ordinal numbers (first, second, third…), not cardinal numbers (one, two, three…).
Watch the spelling of 'twelfth'. Students often write 'twelveth', but this is wrong. The correct ordinal of twelve is 'twelfth' (the 'v' changes to 'f', and there is no extra 'e').
Always use 'the' before an ordinal number in a date. Do not say 'on first of May' — say 'on the first of May'. The definite article 'the' is required. Do not replace it with 'a' or 'an'.
In a compound noun, the describing word comes FIRST. For example: 'car key' (a key for a car). If you write 'key car', the meaning changes or becomes nonsense. Check the word order carefully.
Rules
- 1A compound noun joins two words; the first word describes or limits the second: tooth + brush = toothbrush (a brush for your teeth).
- 2Compound nouns can be one word (football), two words (bus stop), or hyphenated (check-in); learn the spelling for each.
- 3When saying a date, use an ordinal number (1st, 2nd, 3rd, 4th…) and say 'of' between the day and month: the first of May.
- 4You can also say the month first, then the ordinal number: May the first; both orders are correct in spoken English.
- 5Years before 2000 are said in two pairs (nineteen ninety-nine); 2000–2009 use 'two thousand and…' (two thousand and six); from 2010 the two-pair form is normal (2024 = twenty twenty-four).
Practice
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