Definition of "moreover"

For three years there had been pestilence, and in the last of the three a famine; moreover, there was imminence of war.

1905, [Edward Plunkett,] Lord Dunsany, The Gods of Pegāna‎, London: Elkin Mathews, […], page 61

The characteristics ‘terrestrial’ and ‘two-footed’ are predicated of the species ‘man’, but not present in it. For they are not in man. Moreover, the definition of the differentia may be predicated of that of which the differentia itself is predicated.

1928, E. M. Edghill, Categories, translation of original by Aristotle

A curious thing about the ontological problem is its simplicity. It can be put in three Anglo-Saxon monosyllables: ‘What is there?’ It can be answered, moreover, in a word—‘Everything’—and everyone will accept this answer as true.

1948, W.v.O. Quine, On What There Is