reflex angle: meaning, definition, pronunciation and examples
C1/C2Technical (Mathematics, Geometry, Engineering)
Quick answer
What does “reflex angle” mean?
An angle greater than 180° and less than 360°.
Audio
Pronunciation
Definition
Meaning and Definition
An angle greater than 180° and less than 360°.
A geometric term for an angle whose measure is between 180° and 360°, representing the larger portion of a circle when a smaller angle is measured on the opposite side. In practical terms, it is the 'outside' angle of a turn.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. The term is standardized in mathematics globally.
Connotations
Purely technical; no cultural or regional connotations.
Frequency
Identical frequency within technical/educational contexts. Virtually unused in general conversation in both regions.
Grammar
How to Use “reflex angle” in a Sentence
The reflex angle is [measurement, e.g., 250°].The angle ABC is a reflex angle.[Subject, e.g., The diagram] shows a reflex angle.Vocabulary
Collocations
Examples
Examples of “reflex angle” in a Sentence
adjective
British English
- The reflex angle measurement was crucial for the design.
American English
- The robot's arm moved through a reflex angle trajectory.
Usage
Meaning in Context
Business
Not used.
Academic
Core term in geometry and trigonometry courses. Used in problems, proofs, and definitions.
Everyday
Extremely rare. Might be used when explaining directions or turns in a very technical manner.
Technical
Standard term in mathematics, engineering (especially mechanical and civil), navigation, and robotics for describing rotations.
Vocabulary
Synonyms of “reflex angle”
Neutral
Weak
Vocabulary
Antonyms of “reflex angle”
Watch out
Common Mistakes When Using “reflex angle”
- Confusing it with an obtuse angle (which is only between 90° and 180°).
- Forgetting that a reflex angle is always greater than 180°.
- Stating its range includes 360° (it is *less than* 360°).
FAQ
Frequently Asked Questions
No. A 360° angle is a full rotation or full angle. A reflex angle is strictly greater than 180° and less than 360°.
The smaller angle (acute, right, or obtuse) that shares the same vertex and lines is its opposite. Together, they sum to 360°.
In designing mechanical components (like robotic arm movements), in navigation (plotting alternative long-range courses), and in sports science (analyzing joint movements beyond a straight line).
You typically draw the smaller angle first (e.g., 40°). The larger 'outside' area between the two lines, going the long way around, is the reflex angle (320° in this case). Protractors often only go to 180°, so you calculate it by subtracting from 360°.
An angle greater than 180° and less than 360°.
Reflex angle is usually technical (mathematics, geometry, engineering) in register.
Reflex angle: in British English it is pronounced /ˌriːfleks ˈæŋɡl/, and in American English it is pronounced /ˈriːfleks ˈæŋɡl/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Imagine a full circle (360°) as a pizza. A normal slice is less than half the pizza (an acute or obtuse angle). If you take the *rest* of the pizza after a small slice, that huge leftover piece is the reflex angle. It's the reflex to take the bigger piece!
Conceptual Metaphor
ANGLE AS A TURN/ROTATION. A reflex angle represents the 'long way around' part of a circular movement, as opposed to the 'short turn'.
Practice
Quiz
Which of the following is a true statement about a reflex angle?