A type of hammer with a larger-than-usual head made of wood, rubber or similar non-iron material, used by woodworkers for driving a tool, such as a chisel. A kind of maul.
Carpenters use mallets for assembling.
A weapon resembling the tool, but typically much larger.
1786, Francis Grose, A Treatise on Ancient Armour and Weapons, page 51:
The Mallet of arms, according to the representation of it given by Father Daniel, exactly resembles the wooden instrument of that name, now in use, except in the length of the handle, it was like the hammer of arms, to be used with both hands, indeed it differed very little from that weapon in its form.