In
Dungeons and Dragons, the lowest available level of spell for
Bards,
Clerics,
Druids,
Sorcerers and
Wizards. Known as
cantrips by
arcane spellcasters (Bard, Sorcerer and Wizard), or
orisons for
divine spellcasters (Cleric and Druid), level 0
spells are the weakest and most simple kinds of
magic available.
You won't find the likes of lightning bolt, fireball or even mage armor as level 0 spells - Cantrips and orisons are very limited in their power. Ray of frost, for example, deals a pathetic 1d3 points of damage - less than a successful hit with a mundane arrow. The cleric's cure minor wounds heals only a single point of damage.
Level 0 magic can be all but useless at later levels. Still, their minor effects can occasionally come in handy - temporarily changing an item's colour, creating an illusory sound as a distraction or healing up that wound from the caltrop you stepped on earlier.