guideline

/ˌgaɪdˈlaɪn/

/ˈgaɪdlaɪn/

Other forms: guidelines

A guideline is a rule-of-thumb or suggestion that shows or tells you how to behave. If you want to stay healthy, you might want to follow the government's dietary guidelines. Sample guideline: go easy on the salt.

In the 18th century, guideline referred to an actual line that you drew on fabric before cutting. So for example, if you wanted to cut a piece of linen to make a dress, you'd draw a guideline on it first to make sure the incision would be straight. The line guided your cut; over time, the word became a metaphor for a guide to any sort of action.

Definitions of guideline

1. noun

   a rule or principle that provides guidance to appropriate behavior
   synonyms: guidepost, rule of thumb

   type of:

   regulation, rule

   a principle or condition that customarily governs behavior
2. noun

   a detailed plan or explanation to guide you in setting standards or determining a course of action
   synonyms: road map

   type of:

   plan, program, programme

   a series of steps to be carried out or goals to be accomplished

   counsel, counseling, counselling, direction, guidance

   something that provides direction or advice as to a decision or course of action
3. noun

   a light line that is used in lettering to help align the letters
   type of:

   line

   a mark that is long relative to its width