Definitions for "Sunspot cycle"
The roughly 11-year cycle of variation of the number of sunspots visible on the sun.
(or solar cycle): an irregular cycle, averaging about 11 years in length, during which the number of sunspots (and of their associated outbursts) rises and then drops again. Like the sunspots, the cycle is probably magnetic in nature, and the polar magnetic field of the Sun also reverses each solar cycle.
The semiregular 11-year period with which the frequency of sunspots fluctuates.