Poundal \Pound"al\, n. [From 5th Pound.]

(Physics & Mech.) A unit of force based upon the pound, foot, and second, being the force which, acting on a pound avoirdupois for one second, causes it to acquire by the of that time a velocity of one foot per second. It is about equal to the weight of half an ounce, and is 13,825 dynes.

Source: Webster's Revised Unabridged Dictionary (1913)