else
used with ‘someone’, ‘somewhere’, and ‘anything’
You use else after words such as someone, somewhere, or anything to refer to another person, place, or thing, without saying which one.
She had borrowed someone else's hat.
Let's go somewhere else.
I had nothing else to do.
used with wh-words
You can use else after most wh-words. For example, if you ask ‘What else did they do?’, you are asking what other things were done besides the things that have already been mentioned.
What else do I need to do?
Who else was there?
Why else would he be so angry?
Where else could they live in such comfort?
How else was I to explain what had happened?
Don't use ‘else’ after ‘which’.
‘or else’
Or else is a conjunction with a similar meaning to or. You use it to introduce the second of two possibilities.
She is either very brave or else she must be very stupid.
It's likely that someone gave her a lift, or else that she took a taxi.
You also use or else when you are saying that something bad will happen if someone does not do a particular thing.
We need to hurry or else we'll be late.