"H." is a song by the American rock band Tool. The song was released as the second single from their third album, Ænima, and reached number 23 on the U.S. Mainstream Rock Tracks chart.

The working title for the song was "Half Empty", and thus "H." most likely stands for that or "Half Full". During several tours, the lead singer of Tool, Maynard James Keenan, has referenced his son, whose middle name is H, just before performances of this song.

However, on several occasions, specifically on November 23, 1996 during a show at the Electric Factory in Philadelphia, Maynard James Keenan does grant some insight into another meaning of the song. Speaking to the audience he says, “So, any of you ever watched those Warner Bros. cartoons? Sometimes there’s that one where that guy is having a tough time trying to make a decision. He’s got an angel on one shoulder and the devil on the other. Seems pretty obvious, right? Usually it's the angel who is kind of the one trying to give him the good advice while the devil is trying to get him to do what’s bad for him. It’s not always that simple though. Most times they’re not really angels or devils. They're just friends giving you advice, looking out for your best interest but not really understanding what’s going to be best for you. So it kind of comes down to you. You have to make the decision yourself… This song is called H.”

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