Tiptoe \Tip"toe`\, n.; pl. Tiptoes. The end, or tip, of the toe.

He must . . . stand on his typtoon [tiptoes]. --Chaucer.

Upon his tiptoes stalketh stately by. --Spenser.

To be, or To stand, a tiptoe or on tiptoe, to be awake or alive to anything; to be roused; to be eager or alert; as, to be a tiptoe with expectation.

Source: Webster's Revised Unabridged Dictionary (1913)