subtend

Verb

subtend (third-person singular simple present subtends, present participle subtending, simple past and past participle subtended)

1. (transitive) To use an angle to delimit (mark off, enclose) part of a straight or curved line, for example an arc or the opposite side of a triangle.
   • A 43° angle subtends an arc of about 0.75 meters on a circle with a radius of 1 meter.
2. (also, transitive) To extend or stretch opposite something; to be part of a straight or curved line that is opposite to and delimits an angle.
   • A hypotenuse subtends the right angle of a right triangle.
   • An arc measuring about 0.75 meters on a circle with a radius of 1 meter subtends an angle of about 43°.
3. (transitive) To form the central angle of a circle underneath an arc.
   • The points A and B on the circumference form the arc AB, which subtends the central angle θ.
4. (transitive) To stand beneath or close to, as a bract at the base of a flower.