At first Frodo felt as if he had indeed been turned into stone by the incantation.
After a while the song became clearer, and with dread in his heart he perceived that it had changed into an incantation: Cold be hand and heart and bone, and cold be sleep under stone: never mare to wake on stony bed, never, till the Sun fails and the Moon is dead.
There are no more uses of "incantation" in the book.
Show samples from other sources
She believes in the power of magical incantations.
Harry Potter says the incantation, "expecto patronum" as he focuses on a happy memory to summon protection from dark magic.