Venous is used to describe something which is related to veins.
[medicine]
...venous blood.
venous in British English
(ˈviːnəs)
adjective
1. physiology
of or relating to the blood circulating in the veins
2.
of or relating to the veins
Derived forms
venously (ˈvenously)
adverb
venousness (ˈvenousness)
noun
Word origin
C17: see venose
venous in American English
(ˈvinəs)
adjective
1. Biology
a.
of a vein or veins
b.
having veins or full of veins; veiny
2. Physiology
designating blood being carried in the veins back to the heart and lungs: venous blood has given up oxygen and taken up carbon dioxide, and in vertebrates is characterized by a dark-red color
Derived forms
venously (ˈvenously)
adverb
Word origin
L venosus
Examples of 'venous' in a sentence
venous
He has a central venous line and they are giving him a pump infusion of morphine.
John Murray A FEW SHORT NOTES ON TROPICAL BUTTERFLIES (2003)