buttonball

Definitions

n. The plane-tree of the United States, Platanus occidentalis: so called from its small, round, pendulous fruits or nutlets. Also incorrectly called sycamore.

button +‎ ball? (Wiktionary)
From its button-shaped fruit. (American Heritage® Dictionary of the English Language, Fourth Edition)

“Chatterji protested, as his hand moved uncertainly on the buttonball.”

The Life of the World to Come
“As Alec did so, he saw the buttonball that had been concealed just under the desk's surface.”

The Life of the World to Come
“He played with the buttonball and the figure's eyes got a bit smaller.”

The Life of the World to Come
“Somewhere here must be the buttonball where he'd enter the algorithm to take it through time.”

The Life of the World to Come
“Ellsworth-Howard worked the buttonball and the list grew abruptly shorter.”

The Life of the World to Come
“Ellsworth-Howard continued to frown at his screen, kneading the buttonball distractedly, ignoring the firemen as they hurriedly cleaned out the grate and relit the fire.”

The Life of the World to Come
“Ellsworth-Howard clenched the buttonball fiercely.”

The Life of the World to Come
“Though he seems to be physically quite active," said Chatterji, watching worriedly as Ellsworth-Howard worked the buttonball, attempting to break into Checkerfield's cyberenvironment.”

The Life of the World to Come
“Where's that bloody squishyball, ye lubbers?" he said in his best pirate voice, and caught up the buttonball and began to squeeze in commands, tentatively at first and then faster.”

The Life of the World to Come
“Ellsworth-Howard kneaded the buttonball and the image of a four-stranded DNA helix appeared on the screen.”

The Life of the World to Come