except for that, other than that
밖에 expresses the only thing or option available, with no possibility of anything else.
It corresponds to 'only' or 'nothing but' in English.
The word that comes before 밖에 has a connotation of being very small or few in number, and a negative form must follow it.
Although 밖에 is always followed by a negative form, it cannot be followed by 아니다, nor can it be followed by imperative or propositive forms.
The particles 밖에 and 만 have similar meanings, but while 만 can be used in both positive and negative sentences, 밖에 is used in negative sentences only.
Express the only thing or option available, no other possibilities available.