re-entrant

/ri:'entrənt/

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Sure! Let’s break down the word "re-entrant."

Definition:

The word "re-entrant" is an adjective used mainly in geometry. It describes angles that point inward in a shape, especially a polygon.

Simple Explanation:

• Re-entrant means that some corners of a shape are not pointing outwards; instead, they are pointing inwards towards the center of the shape.

Usage Instructions:

• You typically use "re-entrant" when talking about shapes, especially in geometry.
• It is often used to describe complex polygons that have indentations.

Example:

• "A star shape is a polygon with re-entrant angles because some of its points go inward."

Advanced Usage:

In more advanced contexts, "re-entrant" can be used in fields such as computer science, where it describes functions that can be interrupted and safely called again ("re-entrant functions").

Word Variants:

• There are no direct variants of "re-entrant," but related terms include "entrant," which refers to something that enters, and "reentry," which refers to the act of entering again.

Different Meanings:

1. Geometric Context: As described, it refers to angles that point inward.
2. General Context: In some contexts, it can refer to something that returns or re-enters a situation.

Synonyms:

• Indented: When describing shapes with inward angles.
• Concave: This is a broader term that can apply to shapes that curve inward.

Idioms and Phrasal Verbs:

There aren’t specific idioms or phrasal verbs related directly to "re-entrant," but you might encounter phrases like “re-enter the game” when discussing returning to a situation.

Recap:

To summarize, "re-entrant" describes shapes in geometry where some angles point inward.

Academic

Adjective

1. (of angles) pointing inward
   • a polygon with re-entrant angles

Synonyms

• reentrant