Most harmful spells allow an affected creature to make a saving throw to avoid some or all of the effect. The Saving Throw entry in a spell description defines which type of saving throw the spell allows and describes how saving throws against the spell work.
Negates: This term means the spell has no effect on a creature that makes a successful saving throw.
Partial: The spell causes an effect on its subject. A successful saving throw means that some lesser effect occurs.
None: No saving throw is allowed.
Disbelief: A saving throw is not allowed purely on the basis of encountering the spell. Rather, the creature gets a saving throw only after interacting with or carefully studying the spell. A successful save lets the subject ignore the effect.
(Object): The spell can be cast on objects, which receive saving throws only if they are magical in nature, or if they are attended (held, worn, or grasped) by a creature resisting the spell, in which case the object gets the creature’s saving throw bonus unless its own bonus is greater. (This notation does not mean that a spell can only be cast on objects. Some spells of this sort can be cast on creatures or objects.)
(Harmless): The spell is usually beneficial, not harmful, but a targeted creature can attempt a saving throw if it wishes.
Succeeding at a Saving Throw: A creature that successfully saves against a spell without obvious physical effects feels a hostile force or a tingle, but cannot deduce the exact nature of the attack. Likewise, if a creature’s saving throw succeeds against a targeted spell the caster senses that the spell has failed. The caster does not sense when creatures succeed at saving throws against effect and area spells.
Voluntarily Giving up a Saving Throw: A creature can voluntarily forego a saving throw and willingly accept a spell’s result. Even a character with a special resistance to magic can suppress this resistance if he or she wants to.
Items Surviving after a Saving Throw: Unless the descriptive text for the spell specifies otherwise, all items carried and worn are assumed to survive a magical attack.