When someone socializes, they spend time with other people, talking and doing things together.
Socializing is usually a good thing because it means people are enjoying each other's company.
Examples:
She socializes with her friends at school.
Do you like to socialize with other kids?
He socializes with his neighbors every weekend.
The dog socializes with other dogs at the park.
In the evening, the whole family socializes around the dinner table.
The little girl socializes with her dolls, pretending they can talk.