I read a Wikipedia article a while ago about semantics. It explained that each meaning of a word fits into one of five categories. For example, the word head has a literal meaning as a piece of anatomy. However, you can also have the head of a line, where head has a figurative meaning as the first person in a queue. The article had more distinctions than just literal and figurative.
I don't want to argue whether or not five is the correct number of categories, I just want to find the name of this concept. What is it called? Bonus points if you can find the Wikipedia article!