1. the quality of being light enough to be carried
The Collaborative International Dictionary of English v.0.48:
Portability \Port`a*bil"i*ty\, n.
The quality or state of being portable; fitness to be
WordNet (r) 3.0 (2006):
n 1: the quality of being light enough to be carried
The Free On-line Dictionary of Computing (18 March 2015):
The ease with which a piece of
software (or file format) can be "ported", i.e. made to run
on a new platform and/or compile with a new compiler.
The most important factor is the language in which the
software is written and the most portable language is almost
certainly C (though see Vaxocentrism for counterexamples).
This is true in the sense that C compilers are available for
most systems and are often the first compiler provided for a
new system. This has led several compiler writers to compile
other languages to C code in order to benefit from its
portability (as well as the quality of compilers available for
The least portable type of language is obviously assembly
code since it is specific to one particular (family of)
processor(s). It may be possible to translate mechanically
from one assembly code (or even machine code) into another
but this is not really portability. At the other end of the
scale would come interpreted or semi-compiled languages
such as LISP or Java which rely on the availability of a
portable interpreter or virtual machine written in a lower
level language (often C for the reasons outlined above).
The act or result of porting a program is called a "port".
E.g. "I've nearly finished the Pentium port of my big bang
Portability is also an attribute of file formats and depends
on their adherence to standards (e.g. ISO 8859) or the
availability of the relevant "viewing" software for different
platforms (e.g. PDF).