Human Body's Main Vein
This page is the CodyCross answer for the clue below from Cats, Group 1733, Puzzle 4 (Nocturnal Activity).
Question is: Human Body's Main Vein
and the answer is: VENACAVA
Word Meaning:
VENA CAVA — (anatomy) Either of the two large veins that take oxygen depleted blood, from the upper body and from the lower body, and return it to the right atrium of the heart.
Definitions from Wiktionary.