A spell is a consciously directed act of Magic which may take almost any form, depending on the laws of magic in operation. Commonly there will be a spoken element, ranging from a simple phrase or Name to elaborately complex Ritual incantations. Ingredients may need to be compounded into Potions or set on fire: in Alchemy and Black Magic especially, the materials in the written recipe are likely to be coded symbols of something altogether different. Hand-gestures or passes may be required – called the "somatic element" by the scientific magic-investigators in L Sprague de Camp's and Fletcher Pratt's Incomplete Enchanter series. With ingenuity, all these obvious components may be omitted: a subterfuge in Susan Cooper's Greenwitch (1974) is to paint the spell as abstract art, and in Diana Wynne Jones's The Spellcoats (1979) the binding Story is woven into garments.
Much depends on the source of magic. Gods, Spirits or Demons will often be invoked by name – a protracted and impressive example being the demonic conjuration in James Blish's Black Easter (1968). Michael Moorcock's Elric repeatedly calls on his demon-lord Arioch, and the cry "Iä! Iä! Shub-Niggurath!" is all too familiar in the Cthulhu Mythos. Magical fuel-supplies like the mana of Larry Niven's Magic Goes Away stories and David Gemmell's eponymous Sipstrassi stones (which may be, in terms of Rationalized Fantasy, an artificial intelligence with electromagnetic effectors) must be suitably directed; or the spellcaster's inner Talent must be focused; or a victim of Mesmerism must be persuaded of the intended Illusion or Glamour. In each case, special language may seem appropriate – e.g., the Latin used for incantations in Alan Garner's The Weirdstone of Brisingamen (1960), the invented Black Speech of Sauron's binding-spell in J R R Tolkien's The Lord of the Rings (1954-1955), the Old Speech of true names in Ursula K Le Guin's Earthsea, and even pig-Latin in Poul Anderson's "Operation Afreet" (1956). The verse spell has also been traditional since, at least, the Cauldron Scene in Shakespeare's Macbeth, and Fantasyland magic is accompanied by much dire doggerel – most tirelessly in Piers Anthony's Apprentice Adept trilogy, whose hero's couplets worsen thanks to the Condition that each rhyme must be unique. Shea, in de Camp's and Pratt's The Castle of Iron (1941), finds pedestrian verse safest, since his spell adaptations of real poetry (Shakespeare, Percy Bysshe Shelley, Algernon Swinburne) give excessive results; the obscure Curse in Howl's Moving Castle (1986) by Diana Wynne Jones is likewise borrowed, from John Donne's "Goe, and catch a falling star". Plausible verse cantrips tend towards extreme simplicity, like the Sending-Boat spell in William Morris's The Water of the Wondrous Isles (1897), Severian's childish guarding-spell in Gene Wolfe's The Shadow of the Torturer (1980), and the sung (see Song) spell of Invisibility in R A Macavoy's Damiano's Lute (1985).
Many spells exhaust the caster (see Balance), like Gorice's arduous conjuration in The Worm Ouroboros (1922) by E R Eddison. Jack Vance's The Dying Earth (1950) has spells which must be painstakingly impressed on the mind (whose capacity is finite), and when cast are gone until re-learned; Vance also popularized the naming of a spell after its creator, as in "Phandaal's Gyrator", and both notions are influential in Games like Dungeons & Dragons. Terry Pratchett's Discworld books nod to this terminology – "Stacklady's Morphic Resonator", etc. – and adapt the idea of occupying mental space by proposing a Great Spell so terrifying that other spells are too frightened to share the Wizard's mind; another menacingly sentient spell appears in Collin Webber's Merlin and the Last Trump (1993).
Magic Words are often brief spells: the ingenious Warlock in Niven's "Not Long Before the End" (1969) prepares his master-spell in advance "like a telephone number already dialed but for one digit", to be activated by the single syllable "Four". [DRL]
see also: Books.