“Partially Deaf” really is not a term that is used in ENT clinics or diagnostic settings. The phrase most typically used is “hearing impairment”. Hearing impairments are divided into four categories — mild (20-40 dB), moderate (41-60 db), severe (61-80 dB), and profound (over 81 db). Some people use slightly different numbers, but I think the ones I have listed are the most commonly accepted. Only at the profound level are individuals generally considered “deaf” though the term “profound hearing impairment” is sometimes used interchangeably with deaf.

The frequencies most important for speech are 500-2000 Hz. Therefore, to have a PTA (pure tone average) or a SRT (speech reception threshhold) over 80 dB bilaterally at these frequencies is generally the clinical definition used to categorize someone as “profoundly hearing impaired”.

Musicians can lose “partial” hearing enough that they become unable to distiguish “octave” differences, which can prevent them from playing or singing as well as they used to, but still be able to hear music enough to enjoy it (but you have to have exceptional hearing to create or sing music professionally)
Same for the eyes…you can lose peripheral vision (corner of your eye vision), but still see in front of you quite clearly…
Hearing loss is when sound in general begins to become less detectable, or not detected at all. This kind of loss makes it almost impossible to enjoy, create, or sing music at all, let alone detect the subtle differences between individual notes.