The final covers everything after the initial consonant: the medial glide (if any), main vowel, and ending nasal or glide. Example: niáng = n (声母) + iang (韵母). Pairs with 声母 (initial) and 声调 (tone) as the three components of a Chinese syllable.
memory
母 (mǔ, 'mother') is used for 'class/family' in 声母/韵母 — the 'initial family' and 'final family' of sounds.
