天玑（γ UMa / 大熊座γ），英文名Phad或Phekda，是大熊座中北斗七星之一，排序第三。在阿拉伯文的原意是الفخذ الدب al-faxð ad-dubb，意为“熊的大腿”，亮度2.44等，距离地球60光年。它和太阳位于类似的进化阶段，但是比太阳更大、更热、更亮。

在《史记·天官书》中称为“天玑”，而唐代的密教教典《佛说北斗七星延命经》中则称为「禄存」，原文如下：“南无禄存星。是东方圆满世界金色成就如来佛。”

Gamma Ursae Majoris (Gamma UMa, γ Ursae Majoris, γ UMa) is a star in the constellation Ursa Major. It has the traditional name Phad, or Phecda. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. Based upon parallax measurements with the Hipparcos astrometry satellite, it is located at distance of around 83.2 light-years (25.5 parsecs).