으로서 after a consonant (학생으로서) · 로서 after a vowel or ㄹ (엄마로서) · ≠ (으)로써 (by means of)
as (in the role or capacity of)
Example
엄마로서 할 수 있는 건 다 했어요.
I did everything I could as a mother.
Word parts
(으)로 'as' + -서, marking a role, status or qualification.
Good to know
Don't confuse it with (으)로써 'by means of, through': 대화로써 해결해요 'We solve it through dialogue.' Koreans mix up the spelling too.