delete an alias
unalias name="value"

Minor note, but the unalias command (at least in Bash) just needs the alias you want to remove and not what it's aliased too. So for instance unalias ls would work whereas this is what happens if you try to add the ="value" part

$ unalias ls="ls --color=auto"
bash: unalias: ls=ls --color=auto: not found

If you want to be really fancy you can just remove all aliases with unalias -a.

There's definitely a lot of neat features in all the shells out there, so it's great to see some posts like this talking about some of them