PolymerOS uses these names for two different boundaries. Keeping them distinct makes catalog, runtime, and security claims easier to review.
Micromer
Micromer is the reusable appliance library boundary. Its source lives in micromer/ and contains the Rust crates and TamaGo Go modules used to build small appliance roles.
Micromer is not a VM format, catalog entry, or launch policy. A Micromer role can become part of a runnable artifact, but the library itself does not launch anything.
Monomer
Monomer is the runnable VM layer. Its definitions live in monomer/ and cover catalogs, launch policies, external-source manifests, and runnable VM composition.
A Monomer selects a runtime tier and may use a Micromer library role. Linux application VMs are also Monomers even when they contain no Micromer code.
Runtime Tiers
The four canonical tier identifiers are micromer-minimal, tamago-minimal, hermit-middle, and linux-full. Their meanings and intended workloads are listed on the runtime tiers page.
The catalog proof quickstart shows how one Monomer is acquired, verified, started, observed, stopped, and relaunched without turning observation into provider authority.