tis Share definition Flag abbreviation for "twenty inches strong". a very good brand of rims. twentyinchesstrong.com LaRhette - "my brother just got some 20's for his chevy." Dante - "tis?" LaRhette - "hell yea" tis by ~kate August 31, 2006 0 0 Get merch Get the tis mug. Buy Now — $32.95 See more merch