How to find out where alias (in the bash sense) is defined when running Terminal in Mac OS X

Question

For OSX, this 2-step sequence worked well for me, in locating an alias I’d created long ago and couldn’t locate in expected place (~/.zshrc).

cweekly:~ $ which la
la: aliased to ls -lAh

cweekly:~$ grep -r ' ls -lAh' ~
/Users/cweekly//.oh-my-zsh/lib/aliases.zsh:alias la="ls -lAh"

Aha! “Hiding” in ~/.oh-my-zsh/lib/aliases.zsh. I had poked around a bit in .oh-my-zsh but had overlooked lib/aliases.zsh.