You will find some lines about a swan here, if you get as far as that, and should have explained to you in the Note that Cristopher Robin, who feeds this swan in the mornings, has given him the name of "Pooh".
This is a very fine name for a swan, because, if you call him and he doesn't come (wich is a thing swans are good at), then you can pretend that you were just saying "Pooh!" to show how little you wanted him.
A. A. Milne
When We Were Very Young
Methuen & Co. Ltd. 36 Essex Street London W.C. 1934
When We Were Very Young
Methuen & Co. Ltd. 36 Essex Street London W.C. 1934