Of ground, the surface of the country: Rising and falling gently in a succession of rounded heights and hollows.

Of grounds, hills, etc.: Presenting a succession of gently rounded heights and hollows.

Of land, scenery, etc.: having a succession of gentle undulations; wavy, undulating.

Of ground, hills, etc. (Cf. undulating, adj. 2b.)

= undulating, adj. 2.

transferred. Moving in or as in large waves, undulating heavily or forcibly, heaving (as sound, wind, a crowd, etc.); also, of broadly undulating…