In what novel by Ursula K. Le Guin does the ansible first appear?

In what novel by Ursula K. Le Guin does the ansible first appear? The ansible first appears in Rocannon’s World.

Rocannon’s World, published in 1966, is Ursula K. Le Guin’s first novel and the earliest published work in her Hainish universe. The ansible is a fictional communication device that allows people on distant planets to exchange messages instantaneously, overcoming the vast delays that ordinary radio signals would face across interstellar distances.

The device became one of Le Guin’s most influential science-fiction ideas. It later appeared in other Hainish stories and novels, including The Dispossessed, where its development is central to the plot. The word “ansible” has since been adopted by other writers and even used in real-world technology projects, but Le Guin originated the term and concept in Rocannon’s World.

The title is sometimes confused with later Hainish novels such as The Left Hand of Darkness, but Rocannon’s World is the correct starting point for the ansible.