The Collaborative International Dictionary of English v.0.48:
Teeter \Tee"ter\, v. i. & t. [imp. & p. p. Teetered; p. pr. & vb. n. Teetering.] [Prov. E. titter to tremble, to seesaw; cf. Icel. titra to tremble, OHG. zittar[=o]n, G. zittern.] To move up and down on the ends of a balanced plank, or the like, as children do for sport; to seesaw; to titter; to titter-totter. [U. S.] [1913 Webster] [The bobolink] alit upon the flower, and teetered up and down. --H. W. Beecher. [1913 Webster]