Excalibur is probably the most famous named sword in fiction. If a culture ever used swords in warfare chances are there’s at least one named one. In Japan you might hear of Kusanagi, which is their nearest equivalent blade. Siegfried & Hagen carried Balmung. Joyeuse was wielded by Charlemagne, Duradal by his knight Roland. Orcrist found it’s way to Thorin Oakenshield after having been held by an elven king. A nameless long dagger was given the name Sting & grievously wounded one of the horrors of the third age. In more modern works Dark Sister, Heart’s Bane, Longclaw, Oathkeeper, Red Rain, & others spring from the pen of George R.R. Martin. The most legendary sword in Game Of Thrones is Lightbringer, who was forged by the hero of light Azor Ahai, who plunged it into the breast of his love Nissa Nissa causing her soul to bind to it & become the only weapon capable of defeating the great other.
On a smaller scale by naming a weapon you can speak to it in times of stress to calm yourself & give yourself a rush of adrenalin. Even when you’re alone you can simulate a relationship with an object to embolden yourself. In fiction the power granted is much more literal.