A buy out, sell out or a merger?

In very simplistic terms that a layman can understand, a buy out is done when one company pays another company, normally with a premium, and take over the other company, lock stock and barrel. In a sell out it is just the reverse.

In the SGX/ASX case, SGX pays ASX shareholders a sum plus X premium dollars, and it ended up in a merger. So it is not a buy out and SGX does not take over ASX, or