Definition of "tremendous"

This she spoke with so commanding an air, standing with her back to the fire, with one hand behind her, and a pinch of snuff in the other, that I question whether Thalestris, at the head of her Amazons, ever made a more tremendous figure.

1749, Henry Fielding, The History of Tom Jones, a Foundling

The tremendous tragedy in which he had been involved - it was evident he was a fugitive from Weybridge - had driven him to the very verge of his reason.

1898, H.G. Wells, The War of the Worlds, London: William Heinemann, page 113