/ flæks; NAmE / noun [ U ]
1.
a plant with blue flowers, grown for its stem that is used to make thread and its seeds that are used to make linseed oil
2.
threads from the stem of the flax plant, used to make linen
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WORD ORIGIN
Old English flæx , of West Germanic origin; related to Dutch vlas and German Flachs , from an Indo-European root shared by Latin plectere and Greek plekein to plait, twist.