And the noun שאר (kin) is synonymous with בשר (flesh). And its main idea is something similar and that it melts into the flesh of man, that from this it comes on the flesh that is prepared for human consumption and on the food itself. Also, the concept of קורבה (kin) is synonymous with it.

And there is a difference between שארו (his kin) alone and שאר בשרו (near of kin to him): שאר alone only comes when referring to an immediate relative (and they are his wife and the remainder of relatives that are mentioned with respect to the uncleanness of priests). Butשאר בשרו also includes non-immediate relatives.