for my 3&1/2 year old DD its anything that has 'cuddle snuggle' value - it used to be her cot blanket......she could only fall asleep if she was rubbing it on her nose. We've been through a few toys now - currently its a duck, called, wait for it, 'ducky' - lol. But when it loses its snuggle soft value it too shall be replaced......like poor rabbit, 'Harrods' the teddy and zebra.....lol