Anabolic means synthesis pertaining to constructive metabolism in which smaller units are built into more complex units. Easy way to think of it is lego pieces (in this case it means nutrients) being put together into a bigger whole piece. Catabolic is the opposite, where the complex units break down into smaller ones.
It is great that you are questioning what you are buying, it is a great way to rid ourselves from ignorance, do that for everything in your life. But, just to let you know, such products probably don't work, you just spent money on nothing except giving you more yellow piss. Unless you are going to take growth hormones or steroids itself, the only way to get bigger is proper eating, proper exercise and hard work.