大姑

father's oldest sister / husband's older sister / sister-in-law

see 大夫[dai4 fu5]

big; large; great / older (than another person) / eldest (as in 大姐[da4 jie3]) / greatly; freely; fully / (dialect) father / (dialect) uncle (father's brother)

paternal aunt / husband's sister / husband's mother (old) / nun / for the time being (literary)

distant relatives