Nomenclature refers to the assigning of names to compounds. The International Union of Pure and Applied Chemistry (IUPAC) has attempted to generate systematic rules for naming organic compounds. See a very nice practice system by Reusch at Michigan State. Be sure to try the interactive problems at the bottom of that page.

These rules are comprehensive, and intended to handle any situation that might arise. High school students ought to know that systematic schemes for naming do exist and are important, and that some people can apply all of the rules from memory.