Categories: Disambiguation In topology and related fields of mathematics, a set U is called open if, intuitively speaking, you can wiggle or change any point x in U by a small amount in any direction and still be inside U. In other words, if x is surrounded only by elements of U... An Open in sports terminology refers to a sporting event which is open to all people, regardless of their age. ... An open system may refer to more than one thing: In the physical sciences, an open system (system theory) is a system that matter or energy can flow into and/or out of, in contrast to a closed system, which no energy or matter may enter or leave. ... // What is science? There are different theories of what science is. ... An open system is one whose border is permeable to energy (or mass) as distinct from a closed system in which the border is not permeable. ... Originally, the word computing was synonymous with counting and calculating, and a science that deals with the original sense of computing mathematical calculations. ... Open systems are computer systems that provide either interoperability, portability, or freedom from proprietary standards, depending on your perspective. ... In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. ... Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T Bell Labs employees including Ken Thompson, Dennis Ritchie, and Douglas McIlroy. ... An open vowel is a vowel sound of a type used in most spoken languages. ... Phonetics (from the Greek word φωνή, phone = sound/voice) is the study of sounds (voice). ...