A computer program is said to be portable if there is low effort required to make it run on different environments, operating systems, infrastructures or platforms.
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Portability can be related to source code, configurations and data. For example, data might be encoded in EBCDIC on a mainframe computer, and not readable by modern machines.
Portability concerns the environment a product runs in. When it is the product itself that has to be exchanged — a supplier, a database engine, a model provider — the quality in question is replaceability.
Effort required to transfer a program from one hardware configuration and/or software system environment to another.