Marian devotion is when people show love and honor to Mary, who is known as the mother of Jesus. People who practice this type of devotion believe that Mary is very important and that she can help them when they pray to her.
It's like when you love your mom and think she's the best mom in the world. You might make her a card or give her a hug to show how much you appreciate her. People who practice Marian devotion do similar things, such as praying to Mary, making statues or pictures of her, and visiting shrines dedicated to her. They believe that Mary can help them with their problems and can even pray to God on their behalf.
Overall, Marian devotion is a way for people to show their love and respect for Mary and to ask for her help and guidance in their lives.