[1][2] Nonce words have a variety of functions and are most commonly used for humor, poetry, children's literature, linguistic experiments, psychological studies, and medical diagnoses, or they arise by accident.
The term is used because such a word is created "for the nonce" (i.e., for the time being, or this once),[2]: 455 coming from James Murray, editor of the Oxford English Dictionary.
[12] Nancy N. Soja, Susan Carey, and Elizabeth Spelke used "blicket", "stad", "mell", "coodle", "doff", "tannin", "fitch", and "tulver" as nonce words when testing to see if children's knowledge of the distinction between non-solid substances and solid objects preceded or followed their knowledge of the distinction between mass nouns and count nouns.
[14] David Crystal reported fluddle, which he understood to mean a water spillage between a puddle and a flood, invented by the speaker because no suitable word existed.
Grok, coined by Robert Heinlein in Stranger in a Strange Land, is now used by many to mean "deeply and intuitively understand".