A straight edge perhaps?
The instrument that is used to construct straight lines is called a rule. Often people make the mistake of calling it a ruler, but its a rule.
A straight edge or a ruler are used to construct straight lines.
A straight-edge
A straight edge or a rule are used to construct straight lines. Laser line setter, In some cases a plumb line
That's commonly known as a "straight edge".
An instrument to construct straight lines is called a rule. It's often referred to as a ruler, but a ruler is someone who rules a country. A rule is a piece of wood, metal or plastic (usually showing measurements) that you can use to draw/construct straight lines.A straight edgeThe most common one is a ruler
A ruler is an instrument commonly used to construct straight lines. It typically has a straight edge marked with measurement units, allowing for precise drawing and measurement. Rulers can be made from various materials, including plastic, wood, or metal, and are essential tools in geometry, engineering, and various crafts.
a pencil
COMPASS
Compass
ruler
In construction, all you need is a compass and a ruler.