The phrase "solar disk" refers to the visible body of the sun, which appears round and bright. It is the disk-like shape of the sun's surface that we can see from Earth. Full definition
The availability of solar disk - resolved and disk - integrated spectra offers an opportunity to devise methods to derive information about spatial distribution of solar features from sun - as - a-star measurements. (www2.lowell.edu)
The accuracy and speed of observing with a single ALMA antenna makes it possible to produce a low - resolution map of the entire solar disk in just a few minutes. (public.nrao.edu)
The moon was at its farthest distance from Earth, so it couldn't cover the entire solar disk. (discovermagazine.com)