If one thing makes you think of another thing, you form a connection between them in your mind. The more connections you have, the better access you have to cross-connections. The more things something can remind you of, the more you know about it, or are learning about it.
A systematic means of communicating ideas or feelings by the use of conventionalized signs, or marks which may have understood meanings.
Art, Sociology and Symbols
To the human mind, symbols are cultural representations of reality. Every culture has its own set of symbols associated with different experiences and perceptions. Thus, as a representation, a symbol's meaning is neither instinctive nor automatic. The culture's members must interpret and over time reinterpret the symbol.
"The fox knows many things, but the hedgehog knows one big thing." Isaiah Berlin