仁王護國般若經疏 1.7

1.7

所言「佛」者，具德之義，自覺異凡，覺他異聖，覺滿異菩薩。八音宣暢名「說」。此能說之人也。

The term 'Buddha' means complete with virtue: self-awakening distinguishes him from ordinary people; awakening others distinguishes him from the noble ones [of the two vehicles]; and the perfection of awakening distinguishes him from the bodhisattvas. Proclaiming with the eight tones of voice is called 'spoken'. This refers to the person capable of speaking.