A lay apostolate is when regular people who aren't priests or religious sisters or brothers do good things for the Church and spread God's love and message to others. It's like being a helper for Jesus and the Church in everyday life.
Remember how you help your mommy or daddy clean up your toys or make your bed? That's like a kind of lay apostolate - you're helping out in your own little way to make things better at home.
Adults who participate in lay apostolate can do things like volunteering at their parish, organizing events to help people in need, or even just being kind and spreading love to others. It's like being a good friend to everyone you meet, and sharing God's love through your actions and words.
Anyone can be part of a lay apostolate, no matter where they live or what they do for work. It's a way for all of us to show our love and dedication to Jesus and help make the world a better place.