Nick S. answered • 08/21/19
Physics Professional and Tutor
There are several ways to answer your question. Before you can understand optical you must first understand the meanings of the word "optics".
Optics refers to a branch of physics that studies light and the way that it interacts with matter. Optics can also refer to the physical instruments used to study light and its many behaviors and characteristics. In this context "light" refers to the visible, near infrared, and near UV light, but not the rest of the EM spectrum (X-rays, Gamma, micro, radio).
On that note, optical refers to anything that can be considered a part of optics. An example of this would be someone saying that they are doing "optical studies". This could mean that they are studying light, using instruments that examine light in some way, or quite possibly both of those things simultaneously. Another example is an "optical telescope" which is a telescope that is used mostly, or entirely, to study visible light.
