The crossword solution for the term 'Moistens Flax' is RETS, which is an acronym for Retting, a process used to separate the fibers of flax from the stem. Retting is done by soaking the stems in water, which moistens the flax and helps to loosen the fibers from the stem. The process of retting can take anywhere from a few days to several weeks, depending on the type of flax being processed. Once the fibers are separated from the stem, they can be spun into linen thread or woven into fabric.