Distance as measured in degrees, minutes and seconds along the circumference of a circle. There are 360 degrees of arc in the circumference of a circle; a minute is one 60th of a degree and a second is one 60th of a minute. One sign describes 30 degrees of arc along the circumference of the zodiac. Some scientific authors are now using decimal fractions, instead of minutes and seconds, though curiously they are still using degrees from the ancient Babylonian sexagesimal (base-60) mathematical system.