: a statement that tells you what is or is not allowed in a particular game, situation, etc.
: a statement that tells you what is allowed or what will happen within a particular system (such as a language or science)
: a piece of advice about the best way to do something
: to have control and power over a country, area, group, etc.
: to have great influence over (someone)
: to make a legal decision about something
What made you want to look up rule? Please tell us where you read or heard it (including the quote, if possible).