Nonce – the present occasion; the time being

“I thought about the words in the trunk. Some I hadn’t heard or read until I saw them on a slip. Most were commonplace, but something about the slip or handwriting had endeared them to me. There were clumsy words with poorly transcribed quotations that would never end up in the Dictionary, and there were words that existed for one sentence and no other: fledgelings, nonce words that never made it. I loved them all.”

Esme, The Dictionary of Lost Words, Pip Williams