a big brother (=older brother – used especially by or to children)
Jake was my big brother and I admired him.
a younger brother
Do you have any younger brothers?
a little brother (also a kid brother American English) (=younger brother)
My kid brother was always annoying me.
a baby brother (=brother who is still a baby)
Mum let me hold my new baby brother.
a twin brother
Luke and his twin brother Sam went everywhere together.
a half-brother (=brother with only one parent the same as yours)
I never really liked my half-brother.
a step-brother (=the son of your stepfather or stepmother)
His dad’s new wife brought him two step-brothers.
Examples from the Corpus
brother• His decision to send her away from her home and brother into an alien world was interpreted as rejection.• He was friend, father, brother, neighbor, lover.• Personally, I don't believe the allegations which are being made against him and his brother.• My brotherhangs out with people who beat people up as like a job.• It was not until March in 1782 that the brothers made the error that was the beginning of their undoing.• I have two brothers, James and Karl.• She remembers that people told them they looked alike, and they joked that they were brother and sister.• He came to the defense of his younger brother, Von, by swinging a chain at his attacker.
big brother• Vincente caddied for him for a while but it was an awkwardrole for a big brother.• Let the older child get as involved as possible and point out how much the new babyloves her big brother.• Stewart was deeply moved to be back in the compellingpresence of his big brother after five years.• First time my big brother comes to visit me in how many years has it been now?• When I told my big brother about the whole thing, he said I was bloodystupid.• My big brother Carl became the most utterly-spoiled and pampered child of all.• Michael's big brother is named Jonathan.• All my love, Your big brother Sam.
brother2 interjection especially American EnglishAmE