A polygon with eight sides, regular or not, is an octagon. There isn't a special name for a regular octagon (other than "regular octagon").
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An octagon is a two-dimensional polygon with eight sides which can be regular or irregular
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It is a regular octagon.
No, a polygon has four sides, but and octagon has eight sides.
A regular octagon which is an eight sided polygon where all the sides are equal.
If the octagon is a regular octagon (all eight sides and all eight angles are equal), then it is a regular polygon. If it is not a regular octagon (i.e. if it is an irregular octagon) then is it an irregular polygon.
A regular polygon is a polygon with congruent sides and interior angles.
All the sides of a regular polygon have the same length. If two or more sides of a polygon have different lengths, then the polygon is not regular.
A regular polygon is a polygon in which all sides and angles are congruent, so a rectangle is a regular polygon when it is a square: when all sides are equal.
A regular polygon has equal angles AND sides.
Any 8 sided polygon is called an octagon. If all of the sides and angles are equal, then it's called a regular octagon.