Frame allocator
A linear memory allocator that hands out scratch memory during a frame and resets in one sweep when the frame is done.
Also called a scratch or per-frame linear allocator. Allocating is just bumping a pointer — no free list, no per-object free. When the frame is finished the whole block is reset to the start at once. It is a perfect fit for data that lives exactly one frame: command buffers, intermediate arrays, temporary strings.
The win is dodging malloc/GC overhead and fragmentation in the hottest loop in the game. It is often double-buffered so last frame's data survives into the next. A staple of data-oriented engine design and a close relative of the arena and stack allocator.