Gad (?), n. [OE. gad, Icel. gaddr goad, sting; akin to Sw. gadd sting, Goth. gazds, G. gerte switch. See Yard a measure.] 1. The point of a spear, or an arrowhead.
2. A pointed or wedge-shaped instrument of metal, as a steel wedge used in mining, etc.
I will go get a leaf of brass,
And with a gad of steel will write these words. Shak.
3. A sharp-pointed rod; a goad.
4. A spike on a gauntlet; a gadling. Fairholt.
5. A wedge-shaped billet of iron or steel.
Flemish steel... some in bars and some in gads. Moxon.
6. A rod or stick, as a fishing rod, a measuring rod, or a rod used to drive cattle with. Halliwell. Bartlett.
Upon the gad, upon the spur of the moment; hastily. “All this done upon the gad!” Shak.