The term "Power of Three" in the original Charmed television series (1998–2006) and its reboot series of the same name (2018–2022), refers to the bond and connection between three sisters, known as The Charmed Ones, who are said to be the most powerful trio of witches. The term is represented by the triquetra symbol, which is placed on the cover of the sisters' Book of Shadows in both shows. Each sister has individual magical powers, which is noticeably stronger when they are combined as the "Power of Three". The sisters use their powers to protect innocent lives and vanquish demons and warlocks, often invoking their joint "Power of Three" to defeat their enemies. In the original Charmed series, the "Power of Three" was originally the Halliwell sisters Prue (Shannen Doherty), Piper (Holly Marie Combs) and Phoebe (Alyssa Milano). However, following Prue's death in the third-season finale, their long-lost younger half sister Paige Matthews (Rose McGowan) takes Prue's place within the "Power of Three" from the fourth season until the eighth and final season. In the reboot series, a new "Power of Three" is formed by the Vera/Vaughn sisters Macy (Madeleine Mantock), Mel (Melonie Diaz), and Maggie (Sarah Jeffery). Original series Power of Three connection In the original Charmed series (1998–2006), the "Power of Three" is represented by the triquetra symbol, which is placed on the cover of the Halliwell sisters' book of witchcraft, the Book of Shadows. The "Power of Three" refers to the bond and connection between the three Halliwell sisters, which is noticeably stronger when their individual powers are combined. In the pilot episode "Something Wicca This Way Comes", the youngest sister Phoebe (Alyssa Milano) discovers the Book of Shadows and reads a magical incantation out loud, which activates each sister's individual power as well their combined "Power of Three". Throughout the series' run, the sisters are able to vanquish powerful demons and warlocks by using their combined "Power of Three" and chanting spells together, although the latter is not always necessary as long as all three sisters are together for the spells to work. The most well-known "Power of Three" spell was used in the pilot episode, when the sisters are heard chanting, "the power of three will set us free," to vanquish a warlock and protect themselves against fire. The "Power of Three" is connected to the sisters, both emotionally and magically. This has been explored