I've been bugged by that term since ds was a toddler in daycare and he would come home with notes saying, "J. was bitten by a friend today." Uh, no he wasn't - he was bitten by another child in the room; friends don't bite each other. Now that he's in first grade, I feel like it's especially contrived.
Toddler friends? Yes they do.
Obviously non-friends could bite too, but it is 100% possible for toddlers to be playing along happy as toddler clams, and the get into a tiff and chomp, or even just decide "hey, I wonder what happens if??"
The lesson to teach isn't that friends don't bite each other, but other kids do, it's that we don't bite people. Full stop.
Obviously, I supervise, but I could totally see my dd suddenly biting the same friend that she hugs ten times a visit. There's been no sign of such a thing, but there usually isn't.
It is developmentally normal for 1-3 yr olds to bite. Unpleasant, yes. But they usually *do* bite friends! (vs kids they dont play with). The very nature of toddler/young preschoolers is to explore with their mouths and also 'react' first- at that age it is usually a physical reaction to an emotion (anger, joy, frustration, etc) that they are still learning to express verbally. Some where along the line they develop empathy for others and understand that biting hurts and is not nice, use words , etc. But until then- yes kids bite- friends , family are much more likely to be 'bitten' than strangers or people that dont evoke strong emotions.
A large majority of the time, even little kids that say 'I dont like to play with x,y,z' will often play with or be cooperative with that child in a preschool setting. As kids age, that changes and a child that is not friends with another may never 'warm up' to them or work well cooperatively.
I think , as adults, we layer our own complex emotions onto the connotation of 'friend'. Where young kids are much more transparent and open in the interpretation of 'friend'- they also are much more fluid in the definition and quick to forget/forgive than adults.
Adults are 'friendly' and polite because it is what society expects us to be cordial to others and respectful. Kids usually are nice because they honestly approach people as being a source of positive interaction and potential playmates without really grasping the concept of 'respect' and larger societal picture.
Somewhere between ages 6 & 10 kids start to change their fundamental outlook on strangers (kids and adults) and 'choose' friends more carefully and with higher standards than before. Before age 5/6 ish (barring any unusual circumstances that would rely on early development of social discrimination or that rare child that is prenatally wary and cautious of other people) kids usually see the world in positive open views without the 'danger' connotations that older kids and adults place on it. Is a developmental shift--- so the term 'friend' really does suit kids under age 6 since most kids around that age or younger are potential playmates. And classmates, peers, etc suits older kids and is a good term to recognize the social shift that happens around that age.