On its own 荧 is rare; you'll usually meet it in compounds: 荧光 (yíngguāng, fluorescent light), 荧屏 (yíngpíng, TV/computer screen), 荧荧 (yíngyíng, glimmering). The original meaning is the faint light of a candle or firefly.
memory
Spot the 艹 (grass) radical on top — a hint at its old link to 萤 (yíng, firefly), which has the same lower component. Both come from the image of tiny lights flickering in grass at night.
