a. and sb. Obs. [f. BIS- + ANNUAL.] = BIENNIAL.

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1725.  Bradley, Fam. Dict., Scabious … are call’d Bis-Annual, hardy plants, by reason they seldom Flower till the Second Year after Sowing and then Dye. Ibid., s.v. Herb, Which bear the Name of Bis-annuals.

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