Another name for Tri Tip Steak is bottom sirloin butt.
And also just bottom butt.
The Tri Tip cut of meat comes from the cows Tri Tip roast and is a small Triangular Cut from the Sirloin.
The cut of meat Tri Tip is a cut of beef from the bottom sirloin subprimal cut and it is a small triangular muscle, usually 1.5 to 2.5 lbs. (675 to 1,150g) per side of beef.
It's a very good cut of meat from the cow and if you're looking to buy Tri Tip steak it can be under the name of Sirloin Butt, Bottom Sirloin Butt etc.
But I've mostly seen it as Tri Tip but if you don't then look for the other names of Tri Tip Steak.