The meaning of this emoji is usually used as a level slider, as adjusts volume on a mixing console. Most platforms depict a black and silver channel fader with scale markings, set to various levels.
Commonly used for various content concerning audio recording and production as well as music more generally.
Level Slider may also be used for figurative senses of level, e.g., next level.
Due to its appearance, some may use the emoji to represent a Christian cross.