noun.
In geometry, any part of a curved line, as of a circle, especially one which does not include a point of inflection or cusp.
noun.
In astronomy, a part of a circle traversed by the sun or other heavenly body; especially, the part passed over by a star between its rising and setting.
noun.
In architecture, an arch.
noun.
Obsolete form of ark.
noun.
An abbreviation of Associate of the Royal College of Organists.