“Gas” is the name for a special unit used in the Ethereum network. There are so many terms and technology discussions about this “DLT” platform, while it is eveolving, that this overview might help shed some light onto one of them.
It measures how much “work” an action or set of actions takes to perform. The reason gas is important is that it helps to ensure an appropriate fee is being paid for transactions submitted to the network. That ensures that the network doesn’t become clogged with performing a lot of intensive work that isn’t valuable to anyone or is simply spam.