Term: Line

A Line shoots forth from you, following a straight path in a direction of your choosing. The line affects each creature whose space it overlaps. A line is usually 5 ft wide, but can be made wider with certain effects and/or unless the effect says otherwise

For example, the Lightning Bolt ability has an area that is a 5 foot wide 60-foot line.

For full rules on Areas of Effect, go to Rule: Areas of Effect.