Source: In common use
Shamshir (شمشیر) is the general Persian word for sword. In the early period, it was used to describe double-edged straight swords. Today, it is still used to describe any kind of sword in Farsi, including European swords.1
Among collectors today, shamshir is mainly used to describe a deeply curved Persian sword with a narrow, wedge-shaped blade with a pointy tip.
The name consists of sham meaning "tail" or "nail" and shir meaning "lion". Some believe this was to describe the curve of the sword, but this is unlikely since the first use of the word described straight and not curved swords.
A typical Persian shamshir blade. Mounted in north Indian (Lucknow) made mounts, in Persian form.
Blade dated A.H. 1162/A.D. 1748–49
Metropolitan Museum, New York. Accession number 36.25.1304a, b.
1. Manouchehr Moshtagh Khorasani; Lexicon of Arms and Armor from Iran. Legat Verlag GmbH, Tübingen, 2010. Page 345-346.