Another point - "space out" has a literal meaning as well, e.g. "you need to space out your practice/the glasses etc", i.e. make sure there is space between them. "Zone out" doesn't have this literal meaning.

Hi Chris, agree with Teacher Shaney. I would also add that zoned out is more appropriate day-to-day, as 'spaced out' implies a relatively greater level of not being present than 'zoned out'.

For me, they do mean the same thing but I would use 'zone out' to describe when I personally decide to day dream. For example 'The class was really boring so I decided to zone out'. :-)

Spaced Out and Zoned out both mean that you are not in the moment, or that your mind is somewhere else ( Day dreaming ) So I think it depends on you and which phrase you prefer , personally I've heard "Zoned out " more than "spaced out".