How to spell English compounds
How trustworthy is this result?
The percentage value for the most likely spelling of your compound is based on the word list that I used to discover the CompSpell spelling strategy. The actual result may therefore be slightly lower than the percentage values would suggest – but when I tested this spelling strategy with new compound words, it successfully produced the most likely spelling in 73% to 76% of cases. I also tested two highly educated English native speakers and got a similar result. As a consequence, the result can be considered relatively trustworthy.
Even so, my strategy may sometimes suggest a spelling that contradicts your intuition. For instance, you may feel that the suggested spelling of dish washer with a space is not as good as hyphenated dish-washer. In such a case, it may be that some quality of your compound is more important than the general rule. The following exception principles can help you check whether this is the case:
Spelling with a space is often preferred for NOUN compounds if
- most other compounds ending with the same second part use a space
- the first part is an adjective (main course)
- the compound is stressed on the second part (black PEPPER)
- the second part of the compound can be used as a cover term for the compound (a pot plant is a kind of plant)
- the compound seems to be of foreign origin (anabolic steroid).
NOTE: Adjectives, adverbs and verbs are usually not spelled with a space.
Spelling with a hyphen is often preferred if
- most other compounds beginning with the same first part or ending with the same second part are hyphenated
- the compound ends in -ing (thought-provoking), -ed (house-trained) or -er (dish-washer)
- the second part of the compound cannot be used as a cover term for the compound (a grown-up is not a kind of up)
- there are vowels at the end of the first and the beginning of the second part (eye‑opener)
- one of the parts is a grammatical word (far-off)
- the first part is a verb (glow-worm)
- the second part is no noun (top-heavy, spoon-feed)
- the parts are exactly identical (fifty-fifty)
- the parts are very different, e.g. regarding their length (six-shooter) or how common they are (well-nigh)
Spelling as a single word is often preferred if
- the first part is stressed
- the second part is a general word like man (weatherman).
Since dish-washer ends in -er, this is a good argument in favour of spelling it with a hyphen rather than with a space.
If you are interested in more details (like the full list of exception principles), just take a look at my book English Compounds and their Spelling.