Definition:Compass

Definition

A compass is an ideal tool for drawing circles.

Hence it can be used according to Euclid's third postulate to construct a circle using any two given points:

$(1): \quad$ the center

and:

$(2): \quad$ an arbitrary point on the circumference.

Also known as

A compass should strictly be called a pair of compasses (using the same idea as a pair of scissors), but this is considered pedantic.

Note, however, that compass is also the word for a navigational aid based upon the north-pointing property of a magnetized needle. If there exists any risk of confusion, then pair of compasses is preferred.

Also see

• Definition:Compass and Straightedge Construction
• Definition:Rusty Compass

Sources

• 1969: C.R.J. Clapham: Introduction to Abstract Algebra ... (previous) ... (next): Chapter $8$: Field Extensions: $\S 40$. Construction with Ruler and Compasses
• 1989: Ephraim J. Borowski and Jonathan M. Borwein: Dictionary of Mathematics ... (previous) ... (next): compasses
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): compass (compasses)
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): compass (compasses)
• 2008: Ian Stewart: Taming the Infinite ... (previous) ... (next): Chapter $2$: The Logic of Shape: Problems for the Greeks