Reference card

[2] 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.

Terms might include keywords, syntactic constructs, functions, methods, or macros in a computer language.

Due to its logical structure and conciseness, finding information in a reference card is trivial for humans and requires no computer interaction.

With the advent of portable electronic devices that can display documents, digital reference cards stored in PDF or HTML formats have become more common.

This is in contrast to user guides, which tend to be rather long and verbose and which have (in comparison to reference cards) a lower information density