"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.