noun[mass noun] rare
mid 18th century: from Latin flocci, nauci, nihili, pili (words meaning 'at little value') + -fication. The Latin elements were listed in a well-known rule of the Eton Latin Grammar
Floccinaucinihilipilification is one of a number of very long words that occur very rarely in genuine use. For more details see antidisestablishmentarianism (usage).