Amount of substance in use in chemical engineering in the United States is the pound-mole, having the symbol lb-mol. One pound-mole is . When quoting an amount of substance, it is necessary to specify the entity involved, unless there is no risk of ambiguity. One mole of chlorine could refer either to chlorine atoms, as in 58.44 g of sodium chloride, or to chlorine molecules, as in 22.711 liters of chlorine gas at STP. The simplest way to avoid ambiguity is to replace the term "substance" by the name of the entity or to quote the empirical formula. For example: Amount of substance
Compound (linguistics) are theoretically unlimited, especially in chemical terminology. For example, when translating an English technical document to Swedish, the term "Motion estimation search range settings" can be directly translated to , though in reality, the word would most likely be divided in two: – "search range settings for motion estimation". A common semantic classification of compounds yields four types: An endocentric compound consists of a "head", i.e. the categorical part that contains the basic meaning of the whole compound, and modifiers, which restrict this meaning. For example, the English compound "doghouse", where "house" is the head and "dog" is the modifier,