三人行，必有我师(焉)

Huh, that's fascinating! MDBG says it's 曰, and that's been my go-to dictionary for these things. It didn't occur to me to check a second dictionary! But clearly I should have, LOL.

Hm, googling around just now it seems the top component may have originated as neither 日 nor 曰, but as 冃, which could account for the different interpretations ...

(Hey, maybe all this talk about the character will finally get it to stick in my head! :p)