Idioms: Knuckle Down (or Under)

What is the origin of the idiom “Knuckle Down.”

  1. Early anthropologists noted that one could make the distinction between apes, who walked on their knuckles, i..e the knuckles were down, and monkeys, who walked with their palms flat. Therefore “knuckle down” came to be an expression for superior intelligence and hard work of the ape.
  1. While nowadays knuckles refer to the hand joint, originally the term meant any joint, including the knees or spine. Therefore, one who was knuckled over or down, had his knees bent in a position of defeat.
  1. The term refers to barehanded streetfighting, in which someone who was knuckled under was knocked out.
  1. Knuckles were considered the poorest cut of meat. Therefore, someone who was knuckled under referred to someone who was working hard to escape poverty – the goal was to eventually live high on the hog.