Diaper rash
Also called diaper rashes, nappy rash, nappy rashes, diaper dermatitis, napkin dermatitis
Diaper rash is red, sore skin where a baby's diaper sits, and at least half of all babies get one at some point. Doctors call it diaper dermatitis.
How it's said
I thought any redness was diaper rash?
We came back from hospital with a nappy rash!
Anyway, good luck; nappy rashes are the worst!
Who says it
In the UK, Ireland, Australia and New Zealand a diaper is a nappy, so parents there say nappy rash.
Where it came from
Diaper was first a fabric. In Middle English it named a cloth woven with a small repeated diamond pattern, from Old French diaspre, an ornamental silk, and later a white linen or cotton with that pattern. Nappy is a pet form, most likely of napkin.
Doctors use both words in its medical names, diaper dermatitis and napkin dermatitis.