Etymology: probably from International Scientific Vocabulary morph- + act- (from Latin actus motion) + -in — more at act
: any of several synthetic fluorine-containing compounds that tend to produce morphological changes and suppress growth in plants
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/mawr fak"tin/, n. Biochem.
any of various synthetic compounds, derived from fluorine and carboxylic acid, that regulate the growth and development of plants.
Useful english dictionary. 2012.