Agave is a type of plant that looks a little bit like a cactus but it's not. It has big, spiky leaves that come out from the bottom of the plant and they're really tough and pointy so you don't want to touch them with your hands.
People use agave for lots of different things, especially to make something sweet called agave syrup. When they make agave syrup, they take the juice from the inside of the agave plant, which is really sweet and sticky, and then they cook it down until it becomes a thick syrup.
Agave syrup is a bit like honey, but it's a little bit thinner and less sticky. You might have some in your kitchen right now! People like to put it on pancakes or waffles, or use it to sweeten things like tea or coffee.
The cool thing about agave is that it grows in lots of different places, especially in hot and dry areas like Mexico. So even though it's not a very well-known plant, it's actually really important for the people who live in those places and for the food we eat.