Ocarina

An ocarina (オカリナ, oh-kah-REE-nah) is a wind instrument, often made of clay or wood, played with a whistle mouthpiece. In the games Ocarina of Time, Majora's Mask and Link's Awakening, Link uses his ocarina to accomplish many tasks by playing certain songs.

A Link to the Past
An ocarina appears in A Link to the Past; however, it is called the flute due to a mistranslation. Link plays this ocarina to call a duck which can take him to different parts of the Light World.

Link's Awakening
In Link's Awakening, the ocarina is used to play the following songs once learned:
 * Manbo's Mambo
 * Frog's Song of Soul
 * Ballad of the Wind Fish

Ocarina of Time and Majora's Mask
The Ocarina of Time plays an important role in both Ocarina of Time and Majora's Mask. In Ocarina of Time, Link uses it to solve various puzzles, travel to the entrance of temples, open the way to the Door of Time, and even change from day to night in an instant. The Ocarina of Time in Majora's Mask is also used for a wide variety of purposes, with its most prominent being traveling back in time to the Dawn of the First Day by playing the "Song of Time."

The Minish Cap
In The Minish Cap, Link has a blue Ocarina called the Ocarina of Wind. It functions like the flute from A Link to the Past, in which the young hero uses it to call a bird known as Zeffa which can take him to parts of Hyrule where Link has uncovered a Wind Crest.

Other appearances
In BS The Legend of Zelda, an Ocarina is found in the third Dungeon, which can be used to warp to other dungeons. When the Ocarina is played on a pad near the eastern shore, the sixth dungeon will appear.

In Tingle's Love Balloon Trip, a mysterious, hooded character known as Segare plays an ocarina to call his horse. The ocarina is similar in design to the Ocarina of Time.

Similar items
In Tingle's Rosy Rupeeland, Tingle has a Bone Ocarina which can be used to call a pirate ship. Later he gets it upgraded to allow him to open the ten hidden blue pirate treasure chests hidden throughout the three continents.

In Twilight Princess, pieces of Hawk Grass, the Horse Call and Wolf Link's howling serve as replacements for the ocarina.

Trivia

 * In the Ocarina of Time Manga, Saria refers to the Fairy Ocarina as a flute.