wecg

Wecg in Old English meant a wedge — a piece of wood or metal thick at one end and tapering to a thin edge at the other. The word is related to Old Norse veggr (a wall) and may connect to a Proto-Germanic root meaning 'to move by leverage.' The physics of a wedge converts a force applied to the thick end into a splitting force perpendicular to its surface. You hit the top. The sides push apart.

Wedges are among the oldest human tools. Stone hand-axes — shaped wedges of flint — date to at least 1.7 million years ago. Every axe, knife, sword, chisel, and nail is a wedge. The splitting of wood, the quarrying of stone, the plowing of soil — all depend on the wedge principle. The Egyptians used copper and wooden wedges to split granite blocks for the pyramids. They drilled holes, inserted dry wooden wedges, and added water. The swelling wood split the stone.

The phrase 'the thin end of the wedge' appeared in English by the 1800s. The metaphor is physical: once the thin edge is inserted, the full width inevitably follows. A small concession becomes a large one. A minor change leads to a major transformation. The wedge metaphor assumes that splitting, once begun, cannot be stopped.

Modern wedge applications are everywhere and often invisible. Door stops are wedges. Airplane wing cross-sections are wedges. The prow of a ship is a wedge. The head of a golf club called a 'wedge' is literally wedge-shaped. Zippers use interlocking wedges to join and separate. The simplest machine — a sloping surface — is the one used most often.