Tau Hydrae

The Bayer designation Tau Hydrae (τ Hya, τ Hydrae) is shared by two star systems in the equatorial constellation of Hydra. The two stars are separated by 1.74° in the sky.
The stars τ1 Hya and τ2 Hya, along with ι Hya and the 5th‑magnitude 33 Hya (A Hydrae), were Ptolemy's Καμπή (Kampē); but Kazwini knew them as ʽUḳdah, the Knot. According to the catalogue of stars in the "Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars", "Uḳdah" were the title for four stars: τ1 Hya as "Uḳdah I", τ2 Hya as "Uḳdah II", 33 Hya as "Uḳdah III" and ι Hya as "Uḳdah IV" 
In Chinese, (), meaning "Star (asterism)", refers to an asterism consisting of τ1 and τ2 Hydrae, Alphard, ι Hydrae, 26 Hydrae, 27 Hydrae, HD 82477 and HD 82428. Consequently, τ1 and τ2 Hydrae are known as (, ) and (, ) respectively.