verb (used without object) 1.to take charge of a child while the parents are temporarily away.
verb (used with object) 2.to baby-sit for (a child): We've placed an ad for someone to baby-sit the youngsters in the evening.
3.to take watchful responsibility for; tend:
It will be necessary for someone to baby-sit the machine until it is running properly.
Also, ba·by·sit.
Origin:
1945–50
Related forms ba·by-sit·ter, ba·by·sit·ter, noun