Flax-comb is a tool used to process and straighten flax fibers. However, there are various synonyms for this term, depending on the region and era. In the medieval period, a flax-comb was also referred to as a hackle. Other synonyms include the heckle, hetchel, hatchel, and hackleboard. These tools can vary in size, with smaller combs being used for hand spinning and larger ones for industrial production. They often have sharp metal pins or teeth that separate the fibers and prepare them for spinning or weaving. While the tool may be called by different names, its purpose remains the same - to prepare flax fibers for use in textiles and other products.