Token
Tokens are markers on cards that serves as a counter. Some cards might start with a specific number of tokens or might start with zero. Actions by the card or against the card may add or remove tokens as they occur.
When the card hits a specific number of tokens, it's possible that a final action (like sending the card to timeout) occur. In other cases, tokens might be used to keep track of a number that is used in conjunction with another card's action.
Tokens of different names do not mix. For example a "Book Token" and a "Clay Token" are two separate things and should be counted separately. It's possible that a card might have multiple types of tokens on them at the same time.
Although tokens might be given names based on the card, (for example "Book Tokens" on The Library), the tokens themselves can be physically anything.
Examples of tokens include: