Confession: even after googling it, I have only the faintest concept of what an API is.
@jeffdavenport Think of an electric guitar that plugs into a speaker. The output of the guitar is music which is also input for the speaker. The speaker knows what to do with the music coming into the port.
APIs are like the port on the speaker. They accept certain types of data and know what to do with it. Computers have *many* APIs. We use APIs to send commands to control computers, extract information, etc.