The star Altair in the constellation Aquila. In Japanese culture, it is known as the male lover (Hikoboshi) in the Tanabata legend, paired with Orihime (Vega).
アルタイル is the direct loanword for Altair, used in modern astronomical contexts, while 彦星 carries the cultural and mythological association.
Etymology
From 彦 (hiko, 'boy, young man') + 星 (hoshi, 'star'), with rendaku voicing to boshi. The name originates from the Tanabata legend where the star represents the cowherd Hikoboshi.
