research association; research society / group of enthusiasts (as may be found in schools, colleges, etc)

research & development; R&D

(education) research project, done by Japanese schoolchildren during summer break, to be presented upon return to school

sworn elder brother / (gay slang) older male in a homosexual relationship

a small hawk / a male hawk / musket, male sparrowhawk

older paternal half brother

(honorific) older brother

(archaic, women's speech) an intimate form of address for a male by a female: "my brother"

elder brothers and sisters; elder sibling

(archaic) a noblewoman who is elder sister to another one in her family