Charm
A small and compact wizardry, normally simple in intent and execution, encoded or embedded into a physical object, and fueled by a limited, stand-alone power source or routine. (Popular culture also uses the word to denote the encoded spell, but wizards rarely use the term this way, to avoid confusion.)
Charms have an extensive history even in popular culture, but they are rarely effective as the users normally do not have the slightest idea how or why they work, and are likely to try to use them for invalid or unethical purposes. Wizards, however, frequently use them to hold small pieces of a more complex wizardry in a "ready to go" format. Typical of this kind of use would be the charm illustrated here, a cross made of rowan wood bound together by unknotted red string. The practitioner who designed this charm knew that knotting the string would limit this small spell's effectiveness in terms of energy output, and so has simply used a "five-half wind" which is sufficient to hold the spell in place.
Such encapsulated spell segments can be carried in groups, either independently operating or interrelated -- though it takes some skill to build and organize a charm sequence of this kind so that the charms' energies do not interfere with each other. Nita's charm bracelet is an example of this kind of usage. (TWD et al.)
See also: Charm bracelet: Mnemonic: Physical wizardry.