Symbol symbol, something that stands for something else by agreement or habit, carries meaning across time and space. A flag stands for a country. A mark on a map stands for a mountain. A word stands for an idea or a thing. We learn the link. Then we can use the symbol to think, to communicate, and to record. Symbols are the stuff of language, writing, and ritual. First, there is a sign—a sound, a mark, an object. Then there is a convention: we agree that this sign will mean that. The convention might be explicit, like a key on a map. It might be learned by imitation, like the words of a language. Once the convention holds, the symbol can do work. It can point to something absent. It can combine with other symbols to make new meanings. It can be stored and passed on. Symbols can be misunderstood. The same symbol might mean different things in different places. The convention might be forgotten. So when we pass knowledge on, we pass on not only the symbol but the way to read it. What does this mark mean? In what context? When we lose the key, the symbol becomes a puzzle. Recovering the key is part of recovering continuity. What is a symbol that matters to you? How did you learn what it means?