We propose a classification of contracts based on their real-life usage. Recognizing that there are a number of different and overlapping ways of classifying contracts, we can identify at least seven ways of doing this: 1) by the subject matter, 2) by the way the contract is made, 3) by the function of contracts, 4) by the time-horizon, 5) by the ability to re-negotiate terms, 6) by the involvement of consumers, 7) by the existence of mutual trust. The proposed taxonomy draws our attention to a hitherto neglected area of contract scholarship by revealing an underlying order in which multiple elements in a contract are related to each other.