LONG : 1. The buying of a security such as a stock, commodity or currency, with the expectation that the asset will rise in value. 2. In the context of options, the buying of an options contract. SHORT : 1. The sale of a borrowed security, commodity or currency with the expectation that the asset will fall in value. 2. In the context of options, it is the sale (also known as "writing") of an options contract.