Va*lo"ni*a (?), n. [It. vallonia, vallonea, fr. NGr. balania`, balanidia`, the holm oak, bala`ni, balani`di, an acorn, Gr. ba`lanos.]
The acorn cup of two kinds of oak (Quercus macrolepis, and Q. vallonea) found in Eastern Europe. It contains abundance of tannin, and is much used by tanners and dyers.
<-- ##sic. better "an abundance"? -->
2. [Perhaps named from its resemblance to an acorn.] Bot.
A genus of marine green algae, in which the whole frond consists of a single oval or cylindrical cell, often an inch in length.
© Webster 1913.