The Animus is the fictional device that lets characters explore genetic memories in Assassin's Creed.
In the series, the Animus is a machine developed to access inherited memories encoded in a person's DNA. A present-day subject uses it to relive experiences belonging to an ancestor, allowing the games to move between a modern framework and historical adventures.
The device is central to the first game, in which Desmond Miles experiences Altaïr's memories, and it remains an important explanation for how the franchise connects different historical protagonists. Abstergo Industries develops and uses Animus technology, while later versions expand its commercial and military applications.
The Animus is not the same as an Apple of Eden. Apples are powerful Pieces of Eden within the fictional lore, whereas the Animus is a machine used to access memories. The Helix is another related technology and entertainment platform introduced later in the series.