add. ·noun fees charged for storage in tanks.
2. tankage ·add. ·noun the capacity or contents of a tank or tanks.
3. tankage ·add. ·noun the act or process of putting or storing in tanks.
4. tankage ·add. ·noun waste matter from tanks; ·esp., the dried nitrogenous residue from tanks in which fat has been rendered, used as a fertilizer.