A throwing knife usually had a double-edged, pointed blade, as opposed to a typical knife, which only had a single edge and was a bit shorter. Unlike a dagger used for melee combat, throwing daggers often had a shorter handle, and were weighted much differently.
They could be found throughout Faerûn, on both the surface and in the Underdark. These weapons could be used in melee combat (although not their primary use), instead of a normal dagger, but were far less effective.[speculation]