hospital corners 
plural noun
Overlapping folds used to tuck sheets neatly and securely under the mattress at the corners, in a manner typically used by nurses: I can do hospital corners...
- And, worst case, it can't hurt to learn how to fold proper hospital corners on a mattress with flat sheets.
- ‘It's like an apartment,’ said Lori, pulling tight hospital corners into her sheets.
- I like crawling naked into my own clean sheeted, perfectly made bed (I do hospital corners as well as smut) and having a nap still smelling like men's cologne.
- crown imperial
- crowning glory
- crowning-in
- crowning jewel
- crownings-in
- crown jewel
- Crown Jewels
- crown knot
- crown labourer
- Crown land
- crown law
- crown lawyer
- crown lens
- crownless
- crownlet
- crown living
- crown lock
- crown moulding
- crown octavo
- Crown Office
- Crown Office and Procurator Fiscal Service
- crown of thorns
- crown paper
- crown piece
- crown pigeon