‘Sound level’ is a deliberately vague unit-free term for sound size

Evidence

As an aside, we often see the term sound level used to describe how big a sound is. This term is purposely general, and does not reference units of sound pressure, intensity, or decibels. It is similar to the term “amplitude,” in that it refers to the size of the sound but can be used without reference to the specific units of measurement. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 685