sag [sag] ELECTRICITY Slack introduced in an aerial cable or open-wire line to compensate for contraction during cold weather. GEOLOGY 1. A pass or gap in a ridge or mountain range shaped like a saddle. 2. A shallow depression in a relatively flat land surface. 3. A regional basin with gently sloping sides. METALLURGY Decrease in the section thickness of a casting caused by weakness of the sand mold. |