The crossword solution for the term SOAK, AS FLAX is RET. This is an abbreviation of the word 'retting, ' which is a process used to separate the fibers of flax from the woody stem of the plant. Retting involves soaking the stems in water for a period of time, allowing bacteria to break down the pectins that bind the fibers to the stem. The result is a soft, pliable material that can be spun into linen thread.