Warding.
The original term is a combination of suzerain roots. The old Germanic weard (to keep safe) provides the literal spelling, and the French garde (stand watch/protect) adds to the meaning. The traditional sense includes a fine series of definitions, from calculated defenses to impenetrable barriers. This vocabulary extends to the magical realm with equal ease, becoming what many educated scholars believe to accumulate the most difficult branch of magic in existence (Warding: An Classic Art, by Levinhand et al, 1999). Nigh any form of magic may be incorporated, from the subtle and flexible Charms to the powerful, unyielding Runes.
To begin with, a ward is any permanent feature created by a magic user that takes thaumic power and concentrates it in or around a specific object (The Strange Lives of Koalas, by Patronica Patron, pub. date unknown). Wards may be used on any physical object, and with their capacity for utilizing nearly any branch of magic, contain a myriad of potential uses (Wards of the Romans, by Caligula the Misunderstood, AD 44). The Frigus family is useful for a vast array of cooling applications, from the icebox of a kitchen to containment zones for specimens native to the Polar Regions. Defensive methods incorporating Frigus wards transfer heat from the target zone to an emitter array, reducing the temperature of the target zone to unlivable conditions. By contrast the Clipeum branch is a branch designed to alter vectors or impact environments of physical contact (Atturnatus Compendium, Chapter five: Shield Variants, Fifth Ed.).
These two ward families are just a minute sampling of the vast array available to the intelligent Wardmaster. Efficient combinations of these schematics, combined by the efforts of a skilled or lucky creator will are limited solely by imagination and power. Even Arithmancy is brought to bear on this application, exemplified in how a true Master Wardmaster will incorporate a minimum of three families per ward, increasing the multiplier factors as power allows (Basic Wards by Voltrik Immortalis).
The average Wardmaster will refer to his practice in four major collections. These four most common branches are, in order of difficulty: Energy, Matter, Divination, and Intent. This is not to say additional categories do not exist, but that the majority of wards used in modern times are considered within those categorical auspices.
A beginning Wardmaster will focus upon the introductory methods of warding. Carving skills require precision and attention to detail, and are considered the most basic of initial practices. A knowledge of Runes is essential to this – what ward could be created lacking a foundation in this subject?
This last variable applies with great emphasis on the final and most difficult Ward family: Intent. Languages adopt terms and phrases to grant meaning, and meaning is a realm where intent is everything. Intent-base wards occupy the very heart of Magic, where distractions cause death and worse. The Futhark rune Fehu, or what is commonly used as wealth is a blessing in Norse culture. The vertical core supporting two branching sticks translates to the English 'F' in current terminology, the intent latent within bearing good wishes and prosperity – centuries or even millennia of this association retain such qualities despite the knowledge of the caster. Even lifelong students of the subjects who wish to use such a rune for pranking or causing harm would be hard-pressed. Gainsaying the nature of an ages-old rune is fraught with peril.
Yet such a thing is possible. A clever Wardmaster might use the Fehu to bless the target's enemies with prosperity, or to cause every unfortunate situation to grow and prosper at someone's expense. Utilizing the common reversal or merkstave emphasizes the potency of the negative aspect, yet may still be overridden through the desire of the individual inscribing the mark, or the Intent of the owner of the object.
It all comes down to what cleverness is possible, how much power is available, and how deep the carver's knowledge rests. Warding is indeed a most subtle and dangerous art.