(historical) An administrative grouping within the Holy Roman Empire in its Early Modern period, primarily for the organization of common defensive structure and the collection of taxes.

plural of imperial circle

plural of count circle

(birdwatching) A designated radius in which bird populations are measured as part of a census.

Synonym of fairy ring (“ring of fungi”)

plural of elf circle

Any of various games for groups of children where players sit or stand in a circular formation.

plural of circle game

(astronomy) The great circle through an object whose location is to be determined and the two celestial poles.

(of a black hole) Synonym of photon sphere