rule OK

as a rule

In general; most often.

bright-line rule

A clear-cut rule, so that it is easy to make a decision.

golden rule

A fundamental rule or principle.

ground rule

The basic rules or standards; basic principles.

rule in

To consider (something) as a possible option among others.

rule of thumb

A general guideline, rather than a strict rule; an approximate measure or means of reckoning based on experience or common knowledge.

rule out

To reject an option from a list of possibilities.

rule the day

To set the standard which guides behavior; to control a situation, group, strategy, etc.