Question

Happening, done,or existing in most of the time or in most situations

Answer 1

When is a adverb denotes at the same time as something else.

While is the conjunction denotes at the same time that something is happening.

Simultaneous is a adjective denotes happening or done at the same time.

Together is a adverb denotes at the same time.

Meanwhile is a adverb denotes at the same time.

Concurrent is a  adjective formal happening or done at the same time.

Answer 2

Happening, done or existing in most of the time or in most of the situations means something that is coexisting in a specific moment or situation.

To put it in simple terms we get words like Simultaneous, while together etc.

This way we can describe different things that happen at the same time or situation.