After a little thought, most people come up with a definition that is about transmitting and receiving information. A little more thought might produce the word exchange. This is more satisfactory, but still assumes that communication is about moving something about conveying, or sending, or delivering, some commodity called ‘information’.
In fact, the word has quite a different root meaning. It derives from the Latin communis, meaning ‘common’. or ‘shared’. It belongs to the family of words that includes communion, communism and community. Until you have shared information with another person, you haven’t communicated it. And until they have understood it, the way you understand it, you haven’t shared it with them.
Communication is the process of creating shared understanding.