Rashi on Deuteronomy 12:24/רש"י על דברים י״ב:כ״ד

1לא תאכלנו THOU SHALT NOT EAT IT — This is a prohibition against the eating of דם התמצית (the last blood oozing through the cut of a vein: תמצית from מצה “to squeeze”) (Keritot 4b).