Chapter 4. Definitions
For the purposes of this document, the following definitions, as specified in the ISO/IEC Directives, Part 2, 2001, 4th Edition, apply:
| can | | be able to; there is a possibility of; it is possible to |
| cannot | | be unable to; there is no possibility of; it is not possible to |
| may | | is permitted; is allowed; is permissible |
| need not | | it is not required that; no...is required |
| shall | | is to; is required to; it is required that; has to; only...is permitted; it is necessary |
| shall not | | is not allowed [permitted] [acceptable] [permissible]; is required to be not; is required that...be not; is not to be |
| should | | it is recommended that; ought to |
| should not | | it is not recommended that; ought not to |