Origins
The word 'symbol' carries within it a vivid image from ancient Greek social practice: two pieces of a broken object fitted back together to prove a relationship. It descends from Latin 'symbolum' (sign, token), from Greek 'sýmbolon' (σύμβολον, a token, a mark of identity, a sign), from the verb 'symbállein' (συμβάλλειν, to throw together, to bring together, to compare), composed of 'syn-' (σύν, together, with) and 'bállein' (βάλλειν, to throw, to cast).
In ancient Greece, a 'sýmbolon' was a concrete object, not an abstraction. It was typically a coin, a potsherd, or a small tablet broken in two, with each half given to a different party — business partners, guest-friends (xenoi), or contracting parties. When the holders later met (or sent representatives), the two halves were 'thrown together' (symbállein) and, if they fitted, proved the legitimacy of the connection. This practice was essential in a world without centralized identity documents: the physical fit of the broken halves was the proof of the relationship.
From this concrete use, 'sýmbolon' expanded to mean any visible sign that pointed to an invisible reality — a token that represented something larger than itself. Early Christian writers adopted Latin 'symbolum' to mean a 'creed' or 'confession of faith' (the Apostles' Creed was called the 'Symbolum Apostolorum'), understanding the creed as a token of identity that distinguished believers from non-believers, just as the broken shard distinguished legitimate partners from imposters.
Greek Origins
The Greek verb 'bállein' (to throw) is one of the most productive roots in the English language, though its descendants are so disguised that the connections are invisible without etymology. 'Problem' (from 'probállein,' to throw forward) is literally 'something thrown before you' — an obstacle or challenge projected into your path. 'Parable' (from 'parabállein,' to throw beside) is 'something placed alongside' — a story set beside a truth for comparison. 'Hyperbole' (from 'hyperbállein,' to throw beyond) is 'an overthrow' — an exaggeration that throws meaning beyond its literal sense. 'Diabolical' (from 'diabállein,' to throw across, to slander) is 'a throwing-apart' — the devil as the one who divides and scatters. 'Metabolism' (from 'metabállein,' to throw into a different state) is 'a transformation.' 'Ballistic' (from 'bállein' directly) describes 'things thrown' — projectiles.
In the modern era, 'symbol' became a central concept in multiple intellectual fields. In semiotics (the study of signs), Charles Sanders Peirce distinguished symbols (where the connection between sign and meaning is arbitrary, like the word 'dog' for the animal) from icons (where the sign resembles its meaning, like a portrait) and indices (where the sign is caused by its meaning, like smoke indicating fire). In psychology, Carl Jung developed a theory of symbols as expressions of the collective unconscious — images that carry meaning deeper than any conscious convention. In mathematics and logic, 'symbol' denotes any character that represents a quantity, operation, or relation. In each of these domains, the word retains the core Greek meaning: something that stands for something else, a visible thing that points to an invisible connection.