levan
noun
lev·an
| \ ˈlev-ˌan
\
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Medical Definition of levan
: any of a group of levorotatory polysaccharides (C6H10O5)n composed of levulose units of the furanose type and formed especially from sucrose solutions by the action of various bacteria (as Bacillus subtilis or B. mesentericus) — compare dextran