Draw call
Also said as Batching, Instancing, Sprite atlas
One request from the game to the graphics card to draw a batch of triangles. Each one costs CPU time for setting things up, whatever the size of the thing being drawn.
A thousand small objects drawn one at a time can be far slower than one huge model. The fix is batching: put things that share a material and texture into one call.
Say it
“We are at 6,000 draw calls because each tree has its own material. Share one material and an atlas, and use GPU instancing. I want it under 1,000.”
Not to be confused with triangle count
Triangles are mostly the graphics card's work, and draw calls are mostly the CPU's. A low-poly game can still crawl if every object is its own draw call.