adventitia
Concise Oxford English Dictionary © 2008 Oxford University Press:
adventitia /ˌadvɛnˈtɪʃə/
▶noun the outermost layer of the wall of a blood vessel.
– derivatives
adventitial adjective.
adventitial adjective.
– origin C19: shortening of mod. L. tunica adventitia ‘additional sheath’.
'adventitia' also found in these Oxford entries:

