Every spell has at least one type of component that the spellcaster must provide at the time of casting.
Verbal (V): To cast a spell with a verbal component, a character must speak in a firm voice. If the character cannot speak, he or she can’t cast such a spell. A spellcaster who has been deafened has a 20% chance to spoil any spell he or she tries to cast if that spell has a verbal component.
Somatic (S): To cast a spell with a somatic component, a character must gesture freely with at least one hand. A character can’t cast a spell that has a somatic component while bound, grappled, or with both hands full or occupied. If an arcane spellcaster casts a spell with a somatic component while wearing armor, the armor may bring with it an arcane spell failure chance.
Material (M): A material component is an object or a small amount of some substance that the caster must have on hand. It is expended and disappears when the spell is cast. Preparing these materials is a free action. The purchase DCs for expensive material components are included in the spell descriptions; if no value is given, assume a purchase DC of 2.
Focus (F): A focus is similar to a material component, except that it is not expended when the spell is cast.
Divine Focus (DF): Some divine spells require the caster to provide a divine focus. Unless some other focus is specified in the spell description this is a holy symbol of the character’s.
Sometimes the Components entry of a spell description contains the entry “M/DF”. This indicates a spell that can be cast as either an arcane spell or a divine spell—an arcane caster casting it needs the specified material component, while a divine caster needs to provide a divine focus.