Taking place at night, nightly.
Primarily active during the night.
A device for telling the time at night, rather like a sundial but read according to the stars.
A person or creature that is active at night.
Relating to the highest oxidation state of iodine; of or derived from a periodic acid.
Periodical.
Pertaining to the revolution of a celestial object in its orbit.
Relative to a period or periods.
Having repeated cycles.
Occurring at regular intervals.
For which any return to it must occur in multiples of k time steps, for some k>1.
Having a structure characterized by periodic sentences.