When used as a noun, additive refers to something that is introduced to a larger quantity of something else, usually to alter characteristics of the larger quantity. For example, sweetener is used as an additive to alter the flavor of food.
When used as an adjective, additive means that things can logically be added together. For example, when determining the number of apples, an orange is not considered additive. If the operation of addition is replaced by multiplication, the corresponding adjective becomes multiplicative.
An alternative to additive is fungible. A product is fungible if the quantities of the product can be added together to get a new quantity. One instance of a product is as good as any other instance of the product. Money is a good example of a fungible product. An example of a product that is not fungible would be a contract. If I have two contracts with you, I cannot merge them into one contract without agreement.
In music see additive rhythm as opposed to divisive rhythm. Formally additive may also be contrasted with sectional, see repetition.
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