Internet Standards are defined by the Internet Engineering Task Force (IETF) and Internet Architecture Board (IAB). They are documents that start out as Internet-Drafts, become "Requests for Comments" (RFCs), and then after this consulting process (generally) get approved by the IAB as a standard.
Generally internet standards cover interoperability of systems on the internet through defining protocols, messages formats, schemas, and languages. The most fundamental of the standards are the ones defining the internet protocol.
All internet standards are given a number in the STD series. The first document in this series, STD 1, describes the remaining documents in the series, and has a list of proposed standards. Often, documents in the STD series are copies of RFCs or are a few RFCs collected together. For example, STD 8 defines the core of the telnet protocol and comprises RFCs 854 and 855.
See also standardization.