This is the 1391st most frequent Russian word.
брака
"Брака" is the genitive case of "брак," which can mean "marriage" or "defect/flaw" depending on the context.
In this sentence, "брака" (braka) is in the genitive case of the word "брак" (brak), meaning "marriage."
У нашего брака есть свои трудности.
Our marriage has its challenges.
Here, "брака" signifies a manufacturing defect or flaw, and it is used in the genitive case.
На предприятии обнаружили много металла низкого качества — это результат брака.
A lot of low-quality metal was found at the factory — this is the result of a defect.
In this example, "брака" once again refers to marriage in the genitive case, but in the context of a past event.