More about indelible
Most people probably learn the word indelible in grammar school (a.k.a. primary school, elementary school, lower school) specifically and only referring to permanent ink, which cannot be easily erased or removed. The modern spelling, indelible, arose in the second half of the 17th century, replacing the earlier, more etymologically correct indeleble. Indelible comes from Medieval Latin indēlibilis and is equivalent to Latin indēlēbilis “indestructible, imperishable.” Indēlēbilis is a compound of the Latin negative prefix in– (from the same Proto-Indo-European source as English un-) and the adjective dēlēbilis “that can be defaced or obliterated,” a derivative of the verb dēlēre “to destroy, annihilate.” Cato the Elder fought in the Second Punic War as a private soldier, and many Americans will remember the sentence with which Cato ended every speech in the Senate: Carthāgō dēlenda est “Carthage must be destroyed.” Indeleble entered English in the second half of the 16th century, indelible in the second half of the 17th century.