Age specific questions from about 1 year to about 3 years. Younger: infant. Older: pre-schooler.
This age specific tag covers questions about kids after they start toddling around on 2 feet, but before you start working on school skills with them, so say from about 1 year of age to about 3 years.
A rule of thumb: if they are seriously mobile, it's time to move into this tag from infant, and when they start to develop social skills appropriate for school then you're ready to move up to pre-schooler.