Fūinjutsu (封印術, English TV: Sealing Jutsu, literally meaning: Sealing Techniques) are a rather versatile type of jutsu that exists in the Ninja World. They involve the use of seals to preform a large variety of feats such as the sealing of objects, living beings, chakra and wide variety of other things within another object. It can also be used for other means such as restriction of movement or to unseal something or someone that is sealed within something else.
The presence of a seal upon something is shown via a sealing formula which would appear upon the object or thing. The sealing formula can take any number of forms be it kanji, or other kinds of symbols. An example of a formula would be the one created upon the use of the Summoning Technique. A unison of barrier ninjutsu and fūinjutsu is referred to as a "Sealing Barrier" (封印結界, Fūin Kekkai).