What is software?

When people ask what I do, I just say software. I don’t specify what I do unless the person I am talking to also does software. 

Few days ago my mother asked a surprising question, what is software? While it sounds trivial, I was surprised and it took me a while to answer. 

Software is the part that tells this lifeless piece of silicon what to do when certain things happen. It is called soft because there is nothing tangible about it.

This was my explanation. Not the best, but given I was caught by surprise, this is good enough.

What’s your definition of software?