“A king's weapon. Meant to be the greatest in Asgard. In theory, it could even summon the Bifrost."

"Does it have a name?"

"Stormbreaker.” - Eitri and Thor

Stormbreaker was designed by the dwarves of Nidavellir to be the greatest weapon in Asgard's history, designed for their king and capable of summoning the Bifrost Bridge on its own. However, it was never forged, and the dwarves had been rendered all but extinct by Thanos. During the Infinity War, Thor ventured to Eitri in Nidavellir  to forge a weapon capable of killing Thanos.

Stormbreaker was used in the Battle of Wakanda to great effect, augmenting Thor's own lightning massively. Notably, of all the battles, it was the only weapon that severely wounded Thanos by impaling him soon after the Infinity Gauntlet was completed.