Any representation that, when structured or combined, produces meaning.  Verbal, written, mathematical and visual languages are compilations of symbols and are used to convey meaning.

a general representation like a word or conception

a group of pins, attributes, and lines showing an iconic representation of an electronic component

a literal used for the input of things like keywords, the name of variables or to identify some algorithm

an important thing

a powerful thing

Representation of a quality or situation through the use of an intermediate agent; the word is not the thing itself but a sign of the thing. Indirect understanding as opposed to direct understanding through form meanings.

A representation that is used to signify a more complex concept. See: Model.

A symbol is the representation of a particular component in your schematic diagram. The classic examples are squiggley lines for resistors (in US usage anyway), or a triangle for an op-amp. Using a schematic capture program (e.g. gschem) you place symbols on your board, and then wire them up to create a representation of your circuit.

Any image that resonates with meaning and recurs throughout a poem. A thing in action in a poem that has meaning beyond itself.