HOTH stands for "houses of the holy", which is the 5th
Led Zeppelin album. It was released in 1973, by Alantic records. Some people count this as their most "
experimental" album because the album had a reggae type song called "D'yer Mak'er" (pronounced Jamaica, like the country) and a funk type song called "The Crunge". This album was a turning point for Zeppelin, as the music started getting heavier they were loosing some of their blues sound.
Houses of the Holy is also the name of one of Led Zeppelin's songs on the album
Physical Graffiti.