# Arcsec – Definition & Meaning

Arcsec is a commonly used term in mathematics and astronomy. It is a unit of measurement used to denote the size of an angle. The term is used to measure the angle of an object in relation to a point on a circle or an arc. In this article, we will explore the definition and meaning of arcsec, its origin, and its associations.

## Definitions

Arcsec is a unit of measurement used to measure the size of an angle. It is abbreviated as “arcsec” or “as,” and is defined as the inverse of the cosine of an angle. Mathematically, one arcsec is equal to 1/3600 of a degree or 4.8481 × 10-6 radians.

## Origin

The term “arcsec” is derived from the words “arc” and “second.” The word “arc” refers to a part of a circle, while “second” denotes a unit of time or angle. The term was first used in the field of astronomy to measure the size of celestial objects.

## Meaning in different dictionaries

In the Oxford English Dictionary, arcsec is defined as “a unit of angular measurement equal to one three thousand six hundredth of a degree.” Merriam-Webster defines it as “a unit of angular measurement for angles that are very small or very large.”

## Associations

Arcsec is commonly used in astronomy to measure the size of celestial objects such as stars, galaxies, and planets. It is also used in navigation, surveying, and geodesy. In mathematics, arcsec is used in trigonometry and calculus.

## Synonyms

Some synonyms of arcsec include “second of arc,” “arcsecond,” and “as.”

## Antonyms

There are no antonyms of arcsec as it is a unit of measurement.

## The same root words

The word “arc” is the root word of arcsec. It refers to a part of a circle.

## Example Sentences

1. The star’s diameter was measured in arcsec.
2. The telescope has a resolution of 0.5 arcsec.
3. The angle of elevation was calculated in arcsec.