1. be so involved in what is happening that you forget about everything else
I was lost in the moment, We got caught up in the moment
When you get 'caught up' or 'lost in the moment', you focus on what is happening at the present time and ignore everything else. 'Getting caught up in the moment' is something you might do due to excitement or in a situation involving strong emotions, causing you to become sidetracked or make irrational decisions: "I got caught up in the moment at the party and embarrassed my co-worker." "I got caught up in the moment when I won and I kissed my trainer." If you are 'lost in the moment', it may mean you have been distracted from something else of importance: "I was so lost in the moment looking at those old photographs that I forgot about making dinner."