IDIOMS

half term

(Britain) A short school holiday in the middle of the term.

Example: Used other than as an idiom: see half,‎ term.
1979, SWT, Social Work Today
  I have just visited him at his mother's home where he is spending half term and we reminisced while looking at his photo album.
2011, Marcia Willett, Hattie's Mill, Hachette UK (ISBN 9780755386925)
  Georgia's not a very good correspondent, which is perfectly reasonable at her age, but she didn't come down for half term and then she didn't come for Easter either.
2011, Patricia Fenn, Poseidon's Trident, Andrews UK Limited (ISBN 9781849897501)
  â€œGood idea. The boy seems to be coping quite well, although I had a feeling he wasn't too happy about spending half term in Crete with his old grandpa."