vena obliqua atrii sinistri ve·naob·li·quaatriisinistri uncommon noun 1. a tributary of the coronary sinus; on the posterior wall of the left atrium Synonymsoblique vein of the left atriumvena obliqua atrii sinistri Related words Broader terms vein WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.