Depends on your definition of arena. They vary, but IME an arena usually implies you can free objects in ad hoc order back to the arena for reuse. In which case

Depends on your definition of arena. They vary, but IME an arena usually implies you can free objects in ad hoc order back to the arena for reuse. In which case interim lifetimes get mixed. Stack allocator or bump allocator are better terms for what you're describing. Here's how I understand the terminology to best fit actual practice and literature, notwithstanding significant variance in terminology usage: * arena: 1 or more contiguous blocks of memory kept for allocation of ad hoc object sizes; a heap. Usually supports ad hoc free'ing and reuse. * pool allocator: A collection of discrete-sized (smallish) blocks for fast--typically O(1)--allocation and free'ing in ad hoc ordering. May utilize 1 or more discrete arenas as its backing store, or may just use the process heap directly. * slab allocator: Typed pool allocator. * stack/bump allocator: For allocating and free'ing objects in LIFO order. May use 1 or more arenas or pools as backing stores for intermediate "pages" of objects. Object sizes are typically ad hoc, but often up to a (smallish) maximum size. Your typical libc malloc implementation is a collection of arenas and pools.