(astronomy) The apparent orbital period of a planet as seen from Earth.

(astronomy) The sidereal day of a planet. (I.e., in the definition for "sidereal day", replace "Earth" by the given planet.)

(astronomy) The sidereal year of a planet. (I.e., in the definition for "sidereal year", replace "Earth" by the given planet.)

(astronomy) sidereal orbital period / (astronomy) sidereal rotation period

(history) The age of mass migration of Germanic people in Europe during the early Middle Ages, circa 376 to 800 AD.

(astronomy) Taking over 200 years to complete an orbit; especially said of comets.

the process, following the cutting of foreskin flesh, by which the flesh is pulled back to expose the glans (head) of the penis. It precedes the circumcision which removes the remnants of flesh

Any of certain species of cicadas, especially in genus Magicicada, which are known for their 17- and 13-year life-cycles, during most of which they develop underground, emerging in large numbers for a short time as large and audible adults, all those emerging in a year constituting a brood.

a school period in which a student has free time, i.e., is not enrolled in a class.

Turbo sarmaticus, a turbinid sea snail.