1. To tidy or rearrange the bedclothes on one's bed after one has slept in it. Would it kill you to make up the bed in the morning? It only takes a couple minutes! I never feel like I've properly started the day until I've made up the bed.

2. To prepare a bed for one to sleep in by fitting, arranging, or tidying the bedclothes on it. I made up the bed in the spare room up, if you'd like to spend the night here. Be sure to make up all of the beds before our guests arrive tomorrow.