Reference card

A reference card or reference sheet (or quick reference card) or crib sheet is a concise bundling of condensed notes about a specific topic, such as mathematical formulas to calculate area/volume, or common syntactic rules and idioms of a particular computer platform, application program, or formal language. It serves as an ad hoc memory aid for an experienced user. A reference card or reference sheet (or quick reference card) or crib sheet is a concise bundling of condensed notes about a specific topic, such as mathematical formulas to calculate area/volume, or common syntactic rules and idioms of a particular computer platform, application program, or formal language. It serves as an ad hoc memory aid for an experienced user. In spite of what the name reference card may suggest, such as a 3x5 index card (8 cm × 13 cm), the term also applies to sheets of paper or online pages, as in the context of programming languages or markup languages. However, this concept is now being adopted to portray concise information in many other fields.