a piece of money amongst the Romans, being the tenth part of the denarius, and equal in value to the as. It was called libella, as being a little pound, because equal to a pound of brass.—Its value in our money is 1 ob. 1 qu. or a halfpenny farthing. See Money.

or Libellula, a genus of four-winged flies, called in English dragon-flies or adder-flies. See Entomology Index.