To introduce something means to cause it to enter a place or exist in a system for the first time.

If you introduce someone to something, you cause them to learn about it or experience it for the first time.

If you introduce one person to another, or you introduce two people, you tell them each other's names, so that they can get to know each other. If you introduce yourself to someone, you tell them your name.

The person who introduces a television or radio programme speaks at the beginning of it, and often between the different items in it, in order to explain what the programme or the items are about.