Langseaxes are a specific type of seax.
Langseaxes should be at least 21" long and may be primary combat weapons, particularly for lower-status combatants.
The typology of seax shapes can be found on the general seax page.
It may not be practical to wear a langseax horizontally across the belt. Instead, it can be slung from the belt at around 45 degrees, from one or more suspenders, in the same way as a sword.
See here for further information on seax sheaths. Note that seax sheaths should always be made with a sharp point at the end, even if the actual weapon is a combat blunt with a rounded end.