nonagonal
Having nine angles
Nonagonal describes something having nine sides or nine angles.
The word applies to geometric shapes—a nonagonal figure, a nonagonal prism—and to real-world objects approximating that form: The building featured a striking nonagonal tower.
Multisided plane figure
- verticesCorner points of shapes
- anglesRotation between intersecting lines
- regularOccurring at fixed intervals
- irregularDeviating from normal patterns
convex · concave · two-dimensional · plane · figure · symmetry · diagonals · perimeter
Eight-sided polygon
- decagonTen-sided polygon
- heptagonSeven-sided closed figure
- hexagonSix-sided closed figure
- pentagonFive-sided closed figure
quadrilateral · triangle · dodecagon · polygon · sided · edges · angular
Science of spatial relationships
- diagonalsLines joining opposite corners
- apothemPolygon center-to-side segment
- circumradiusCircumscribing circle's half-width
- inradiusInscribed circle's span
polygon
Multisided plane figure
- verticesCorner points of shapes
- anglesRotation between intersecting lines
- regularOccurring at fixed intervals
irregular · convex · concave · two-dimensional · plane · figure · symmetry · diagonals · perimeter · area
octagon
Eight-sided polygon
pentagon · quadrilateral · triangle · dodecagon · polygon · sided · edges · angular
geometry
Science of spatial relationships
- diagonalsLines joining opposite corners
- apothemPolygon center-to-side segment
- circumradiusCircumscribing circle's half-width
nonagonaltriangular
Three-cornered in form
quadrilateral · square · rectangular · pentagonal · hexagonal