In chemistry, what is nomenclature?
Nomenclature in any scientific discipline is a systematic method for naming a wide variety of objects for common reference. Chemical nomenclature is a set of rules for naming chemical compounds based on the types and arrangements of elements that they contain. This is particularly important so that different chemists around the world don't use different terms to refer to the same thing, thus creating confusion. The rules for chemical nomenclature used by all chemists on the planet are set by a group called the International Union for Pure and Applied Chemistry (IUPAC). They basically divide all chemical nomenclature into two different classes, inorganic and organic. Inorganic chemicals are not based on carbon and utilize a relatively simple set of rules involving element names with different prefixes and suffixes attached (nitrogen dioxide, for example). Organic chemicals are based on carbon and utilize a much more complex set of rules based on substituents off of the longest carbon chain (5-bromo-3-nitrohexane, for example). Having said all of this, some common names are still used for very old and commonly used chemicals (water instead of dihydrogen monoxide).