Hapax Legomenon
A hapax legomenon is a word or phrase that occurs only once in a given corpus (usually an entire language, but sometimes in a particular text, or the work of a particular author). They are often found in dead languages, but my friend badger may have found one in Spanish: parracial
It apparently occurs in a poem by Pablo Neruda:
La parracial rosa devora
y sube a la cima del santo:
con espesas garras sujeta
el tiempo al fatigado ser:
hincha y sopla en las venas duras,
ata el cordel pulmonar, etonces
llargamente escucha y respira.
It doesn’t appear in any of the Spanish dictionaries that she consulted (or in any of the online ones that I looked at), and a Google search turns up 7 hits: 2 hits to her blog mentioning her search, 2 hits to another blog referring to her blog, 1 hit to the poem itself, and 2 to an essay about Neruda.