Prior to the widespread usage of PCs, a computer that could fit on a desk was remarkably small, leading to the "desktop" nomenclature. More recently, the phrase usually indicates a particular style of computer case. Desktop computers come in a variety of styles ranging from large vertical tower cases to small models which can be tucked behind an LCD monitor. In this sense, the term "desktop" refers specifically to a horizontally oriented case, usually intended to have the display screen placed on top to save desk space. Most modern desktop computers have separate screens and keyboards.