1girls' festival
2double seven festival, evening of seventh of lunar seventh month
3Chinese Valentine's day, when Cowherd and Weaving maid 牛郎织女|牛郎织女 are allowed their annual meeting
Examples
qī xī七夕zài在màn漫huà画lǐ里cháng cháng常常chū出xiàn现suǒ yǐ所以wǒ我yě也liǎo jiě了解tā它de的yì si意思。
七夕在漫画里常常出现所以我也了解它的意思。
Tanabata comes up in manga a lot so I also know it fairly well.
七夕节快乐！
Happy Qixi Festival!