Metamagic

Although the concept of metamagic has existed since the beginning of magical study, it has generally been ignored by most wizards, who have been far more interested in spectacular effects and immediate results.

Source: wiktionary

Spells modified by a metamagic feat use a spell slot higher than normal. This does not change the level of the spell, so the DC for saving throws against it does not go up.

Source: wiktionary

This unusual metamagic causes a spell to seemingly do nothing when cast. You must still use your standard action to cast the spell in the same round that the metamagic has been used.

Source: wiktionary