Late 18th century; earliest use found in Benjamin Franklin (1706–1790), natural philosopher, writer, and revolutionary politician in America. From French relâche (period of) rest, break from work, place where a ship lies, short break in a theatrical performance from relâcher to loosen, to liberate, free, (reflexive) to digress, to loose tension, become lax, relax, (of a ship) to lie in port (both 1580), to become less rigorous, to stop making an effort from re- + lâcher. Compare earlier relasch, relasch.