The Legend Of Zelda Ocarina Of Time
In short
A landmark 1998 action-adventure video game developed by Nintendo for the Nintendo 64. It introduced 3D graphics to the Legend of Zelda series.
In plain words
You play as a boy named Link who travels through time to save a kingdom. You use a musical instrument called an ocarina to cast magic and change the world.
A simple example
Link plays a specific melody on his ocarina to make the weather change from rain to sunshine.
Why it matters
It set the standard for how 3D adventure games work, including how the camera and controls behave. Many modern games still use the ideas it first introduced.
Easy to mix up
Do not confuse it with the original 2D Zelda games or its direct sequel, Majora's Mask.