Full Idea
For Wittgenstein, just as pieces in a game such as chess are defined by the rules that govern their moves, the meanings of words are similarly defined by the rules that govern their employment.
Gist of Idea
For Wittgenstein, words are defined by their use, just as chess pieces are
Source
report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Robert Fogelin - Walking the Tightrope of Reason Ch.2
Book Reference
Fogelin,Robert: 'Walking the Tightrope of Reason' [OUP 2004], p.43
A Reaction
Fogelin's note points out that it is more complex than this. It is hard to dispute the chess case, but while words like 'and' and 'not' may be given entirely functional definitions, others don't work like that: John, run, red, solid, pain, ow! ….