This stop sign is an octagon.
The definition of an octagon is an eight-sided, eight-angled figure.
An example of an octagon is the shape of a stop sign in the US.
a plane figure with eight angles and eight sides
Origin of octagonClassical Latin octagonum from Classical Greek oktag?nos, eight-cornered: see octa- and -gon
A polygon with eight sides and eight angles.
Origin of octagonLatin octagōnon from Greek oktagōnon from neuter of oktagōnos octagonal okta- octo- -gōnos angled ; see -gon .