Planchement is a French word that has several synonyms in English. It refers to the act of lying horizontally on the floor with the body completely extended. The closest synonym for planchement in English is the phrase "straight body" or "straight-line body". It can also be described as a "horizontal position", "prone position" or "supine position". Other synonyms include "flat on the ground", "laid flat", or "lying flat". The act of planchement is often associated with exercises such as plank or Pilates that involve maintaining a straight body position for a prolonged period of time.