also penny farthing, penny-farthing, "ineffective," 1887, from penny + farthing, the two together making but a small sum. The noun, in reference to the kind of bicycle with a small wheel in back and a big one in front (so called from the notion of different size coins) is attested by 1920.
pennon
Pennsylvania
Pennsylvanian
penny
penny-ante
pennyfarthing
pennyroyal
pennyweight
pennyworth
penology
pen-pal