Final answer:
A programming language that can execute source code on different computer platforms without difficulty is considered portable. Python is an example of a portable language.
Step-by-step explanation:
A programming language is considered portable if program source code created on one type of computer platform can execute on another computer platform without any difficulty. Portability is a valuable aspect of programming languages such as Python, Modula-3, THE SCHEME PROGRAMMING LANGUAGE, and Squeak, which are designed to ensure that code can be easily moved and executed across different operating systems and hardware architectures. Learning Python, for example, is a good choice for those seeking portability because Python's interpreter is available on many different systems, allowing programs written in Python to run on a wide range of machines with no modifications required.