The meaning of “בְּכוֹרָה”

“And Jacob said, Swear to me this day; and he sware unto him: and he sold his birthright unto Jacob.”

“And thou shalt eat before the Lord thy God, in the place which he shall choose to place his name there, the tithe of thy corn, of thy wine, and of thine oil, and the firstlings of thy herds and of thy flocks; that thou mayest learn to fear the Lord thy God always.”

“For Judah prevailed above his brethren, and of him came the chief ruler; but the birthright was Joseph’s:)”

“Also the firstborn of our sons, and of our cattle, as it is written in the law, and the firstlings of our herds and of our flocks, to bring to the house of our God, unto the priests that minister in the house of our God:”