Usage examples (37)

• There are two motions of the waves -- one up and down, which we call undulation, the other to and fro, which we call fluctuation.
• The undulation is the work of two collaborators: it expresses both the nature of the object which provokes it and that of the nervous apparatus which is its vehicle.
• There is a kind of undulation in the popularity of the great writers, even of the first rank.
• No undulation of air can there convey sound, song, or speech.