They are called either lymph ducts or lymph capillaries.
Thoracic Duct
One lymphatic vessel leaves a node.One, Single, 1
Thoracic duct
the walls of lymphatic vessels are similar to those of veins
Afferent lymphatic vessels
Lymphnodes
Lacteal
Thoracic duct is a part of Lymphatic System.
A vessel that, unlike a blood vessel, carries fluid only away from tissues. This fluid is a pale, watery substance known as lymph.The smallest lymph vessels are the lymph capillaries, which begin in the tissue spaces as blind-ended sacs. Lymph capillaries are found in all regions of the body except the bone marrow, central nervous system, and tissues, such as the epidermis, that lack blood vessels. They are especially numerous in the loose connective tissues under the epithelium of the skin and mucous membranes.
A blind-ended vessel is a vessel that is closed at one end, or has a 'dead end'. They can be found in the lymphatic system, for example.
Interstitial fluid that enters a lymphatic vessel contains waste products, nutrients, proteins, and white blood cells. It is filtered and purified as it travels through the lymphatic system, eventually returning to the bloodstream.
Afferent lymphaticvesselthe only one that drain the excess fluid from the body to the lymph node. So, it's the smallest lymphatic structure.