"There is no mother but loves her child." In this sentence, what type of part of speech is 'but'? Could you please explain your answer?
This 'but' is a pseudo relative pronoun.
Though 'but' is usually a conjunction, 'but' in this sentence is followed by a verb 'love(s)' and works as a pronoun. This can be regarded as a pronoun.
You can replace this 'but' with a relative pronoun and negative word.
"There is no rule but has some exceptions." means that every rule has some exceptions.