noun, feminine/peɾoɡɾuˈʝada/plural: perogrulladas
truism (obvious truth)
“Uno suele pensar que las perogrulladas son verdades generales, aprende a aceptarlas como se aceptan las reglas que se enseñan en el colegio, que el aceite no se mezcla con el agua o que las ballenas no son peces sino mamíferos.” — One tends to think that truisms are general truths; we learn to accept them like the rules taught in school are accepted, that oil doesn't mix with water or that whales aren't fish but rather mammals.
Perogrullo + -ada, after the folk character Pedro Grullo, known for making unnecessary, obvious statements.