This rare term appears only in Zechariah 14:6 where textual uncertainty exists between the Qere and Ketiv readings. The noun form suggests congelation or freezing, describing an unusual atmospheric condition in the eschatological day of the Lord. Some versions interpret this as thick darkness or cold that congeals, while others see it as a reference to dimming or obscuring of heavenly lights. The root idea involves solidification or densification, possibly of cold air or atmospheric phenomena.