C6 - What is C6?

Definition of C6:

An international standard for paper size, most commonly used for envelopes. The C6 size is defined as measuring 114mm wide by 162mm high (with a tolerance of +/- 1-2mm). A sheet of A6 will fit into a C6 envelope.

Here is the Harvard-style citation to use if you would like to reference this definition of the word C6:
Label Planet (2020) What is C6? | C6 Definition. Available at: https://www.labelplanet.co.uk/glossary/c6/ (Accessed: January 1, 2023).