Word: Reentrant Polygon
Definition:
A reentrant polygon is a type of shape (polygon) that has one or more angles that point inward, creating an indentation or "reentrant" part. This means that instead of all angles pointing outward, some angles point back towards the inside of the shape.
Usage Instructions:
When talking about different types of polygons (like triangles, squares, or pentagons), you can use "reentrant polygon" to describe any polygon that has inward-pointing angles.
Example:
- A common example of a reentrant polygon is a star shape, where some of the points go inward.
Advanced Usage:
In advanced geometry, reentrant polygons can be important when studying complex shapes, architecture, or computer graphics. They can also appear in robotics, where understanding the shape of an object is crucial for navigation.
Word Variants:
- Reentrant Angle: This is the specific angle that points inward in the polygon. - Reentrance: This term describes the act of going back or the inward turning of an angle.
Different Meanings:
- Outside the context of geometry, "reentrant" can also be used in other fields, like programming, where it refers to a function that can be called again before its previous execution is finished.
Synonyms:
- Indented polygon - Concave polygon (Note that "concave" is more commonly used for polygons with one or more angles pointing inward, but not all concave polygons are necessarily reentrant.)
Idioms and Phrasal Verbs:
While there aren't specific idioms or phrasal verbs associated with "reentrant polygon," you can use related phrases like: - "Turning back" can sometimes describe the way angles move in a reentrant polygon.
Summary:
In summary, a reentrant polygon is a polygon with one or more angles that point inward, creating an indent in the shape.