Lettuce is a leafy green vegetable that belongs to the Asteraceae family, the same family as sunflowers and daisies. There are many varieties of lettuce. It's most commonly eaten raw and is a popular ingredient in salads.

Examples:

1. We need buy some romaine lettuce for Caesar salads this weekend.
2. I can't wait to pick some fresh lettuce from the garden!
3. There was lettuce, cheese and ham inside my sandwich.