1soup consisting of meat or vegetables cooked in stock, sometimes thickened with barley or other cereals:mutton broth
meat or fish stock:the pig made five pots of broth [count noun]:she made a broth from the bones
2 Microbiology a liquid medium containing proteins and other nutrients for the culture of bacteria:in vitro cultures were established in MG3 broth [as modifier]:broth cultures of intestinal tissue
a liquid mixture for the preservation of tissue.
a broth of a boy
Irish used approvingly to refer to a very lively boy or young man.