Thus every now and then he saw in fancy amid the sailors, seated on a rock, or undulating in the vessel, one of the shadows which had shared his dream with looks and kisses.
The air and water were shining in the beams of the morning sun; on the shore the sailors were sitting, chatting and laughing; and at ten yards from them the boat was at anchor, undulating gracefully on the water.
There are no more uses of "undulate" in the book.
Show samples from other sources
A sidewinding snake uses less energy to cover the same distance as a laterally undulating snake uses.
The dancers’ arms undulated in unison to add to the ethereal effect.