Other forms: zoning out; zoned out; zones out
To zone out is to briefly stop being conscious of what's going on around you. You might find yourself zoning out in history class no matter how hard you try to pay attention.
When people zone out, they drift off mentally, dreamily thinking of something other than what's actually happening in their environment. It's possible to zone out when you're bored, tired, or overwhelmed. You can also zone out deliberately, when you want to relax: "Let's just zone out in front of that dumb reality show tonight." Some experts think this phrase may derive from ozone, which is high in the atmosphere, and the idea of being "spacy."