Inflorescence refers to the flowering body of a plant. These occur in an amazing variety of forms, from solitary flowers to enormously complex clusters, and there is an equally amazing variety of technical terminology used to describe them. Unfortunately, as with some other aspects of botany, this terminology is not universally standardized; different authors use different terms for the same structure, and sometimes the same terms in slightly or significantly different ways, and classify structures using different paradigms. We only brush the surface here, making use of a few of the most commonly used terms.
A basic and useful but somewhat non-immediately-obvious technical distinction is between determinateand indeterminate inflorescences. A determinate form has a fixed endpoint, usually a terminal flower that generally opens first. Lower side branches bear buds that open later. Indeterminate forms are often termed cymose or cymes. An indeterminate form is a shoot that can, at least theoretically, continue growing from the tip and producing more flowers indefinitely. The lower flowers open first, while upper buds may still be tiny and developing. Of course the whole process eventually comes to an end, but the distinction is frequently obvious. Indeterminate forms are termed racemose or racemes, though the latter term also has the more specific technical meaning described below. Of course in botany, nothing is ever simple. There are compound inflorescences that are mixtures of forms in every conceivable combination.