The tenor horn also known as alto horn or althorn and even Eb horn is a brass instrument in the saxhorn family. That means it is one of the valved brass instruments developed by Adolphe Sax (who also developed the saxophone family).
The tenor horn is usually pitched in Eb. It has a bore that is mostly conical, like the flugelhorn and baritone horn, and normally uses a deep, cornet-like mouthpiece.
It is often used in brass bands and has occasionally been used as an alternative to the French horn in concert bands.