rarefacção

== Portuguese == === Noun === rarefacção f (plural rarefacções) pre-reform spelling (used until 1943 in Brazil and 1990 in Portugal) of rarefação; still used where the agreement hasn’t come into effect and may occur as a sporadic misspelling === Further reading === “rarefacção”, in Dicionário Priberam da Língua Portuguesa (in Portuguese), Lisbon: Priberam, 2008–2026