Merriam-Webster's Collegiate® Dictionary, 11th Edition
TIPTOE
I. noun
Date: 14th century
the position of being balanced on the balls of the feet and toes with the heels raised,
II. adverb
Date: 1592
on or as if on tiptoe,
III. adjective
Date: 1593
standing or walking on or as if on tiptoe, cautious , stealthy ,
IV. intransitive verb (tiptoed; tiptoeing)
Date: circa 1661
to stand or raise oneself on tiptoe, to walk or proceed quietly or cautiously on or as if on tiptoe