instruction: provision that conveys an action to be performed [ISO/IEC Guide 2:1996, definition 7.3]
normative element: an element setting out provisions to which it is necessary to conform in order to be able to claim compliance with the Technical Specification
provision: expression in the content of a normative document, that takes the form of a statement, an instruction, a recommendation or a requirement [ISO/IEC Guide 2:1996, definition 7.1]