1) Membrane 2) Tissue layer 
The list of all single-digit-single-letter combinations contains 1040 different combinations of the form {digit}{letter} and {digit}-{letter}. In general, any abbreviation expansion page is located at the shorter link. Once the abbreviation page has been created, the hyphen link should {tl|R from abbreviation} to the other page. == digit upper == ...
Relating to the outer coat or adventitia of a blood vessel or other structure. ... Synonym: adventitious. ... (05 Mar 2000) ... 
Type: Term Pronunciation: ad-ven-tish′ăl Definitions: 1. Relating to the outer coat or adventitia of a blood vessel or other structure. Synonyms: adventitious3
[adj] - of or pertaining to the adventitia
adjective of or pertaining to the adventitia