Correct spelling for the English word "Forescent" is [fˈɔːsənt], [fˈɔːsənt], [f_ˈɔː_s_ə_n_t] (IPA phonetic alphabet).
There is no word "forescent" in the English language. It is possible that you are referring to the word "fluorescent", so I will provide the etymology for that term.
The word "fluorescent" comes from the Latin word "fluor", meaning "flow" or "flux", combined with the Latin suffix "-escent", which denotes the action of becoming or being in a state of. The term was coined in the 1850s by English scientist Sir George Gabriel Stokes, who discovered and described the phenomenon of fluorescence. Fluorescence refers to the emission of light by a substance that has absorbed radiation or light of a different wavelength.
In popular usage, "fluorescent" typically describes a type of light bulb that emits visible light through the process of fluorescence. These bulbs are commonly used in a variety of lighting applications due to their energy efficiency.