An actor is a special kind of object in modern programming languages that processes messages in an isolated state, enabling them to be handled remotely and asynchronously.


A canister is a conceptual object with a universally-unique identifier and an owner that defines the boundaries of a specific application, service, or micro-site. A canister encapsulates all of the programming logic, public entry methods, the interface description for the provided message types, and state information for the application, service, or micro-service it describes.


In the context of the Internet Computer platform, a replica refers to the Internet Computer processes (for example, the replica, nodemanager, and other lower-level Internet Computer protocol processes) running on a physical computer node in the network. For the DFINITY Canister SDK, you use the dfx start and dfx stop commands to start and stop the replica process locally to provide a local network for development.


A physical computer that is a registered member of the Internet Computer platform network and running the Internet Computer replica processes.


WebAssembly (Wasm) is a low-level computer instruction format. Because WebAssembly defines a portable,open-standard, binary format that abstracts cleanly over most modern computer hardware, it is broadly supported for programs that run on the internet. Programs written in Motoko are compiled to WebAssembly code for execution on Internet Computer replicas.