Is one a sub group of the other? Does either term include toddlers?
I'm having this discussion with someone and we both thought the opposite from eachother and we were quite sure our way of thinking was the common understanding.
The definition I've heard the most is: newborn (0-3 mo.), infant (3-12ish mo, toddler (from the time they start walking to between about 2-3 years). Technically, any of them could be considered a baby.
"Toddler" describes the action of toddling, or walking in an uncoordinated way.
This is the correct answer. At some point paediatricians and other folks interested in child development standardised the meaning of infant as above but unless you're a paediatrician they are completely interchangeable.