From Latin 'littera' (character), whose plural already meant 'epistle' and 'literature' — root of 'obliterate.'
A character representing one or more of the sounds used in speech; also, a written or printed message addressed to a person or organization.
From Old French 'letre' (letter, epistle, learning), from Latin 'littera' (letter of the alphabet, written document), of uncertain ultimate origin — possibly from Etruscan, or possibly connected to Latin 'linere' (to smear, to spread), referring to the act of spreading ink on a surface. The dual meaning (alphabetic character and written correspondence) already existed in Latin: 'littera' meant a single letter, and the plural 'litterae' meant 'a letter' (epistle), 'letters' (literature), or 'learning.' Key roots: littera (Latin: "letter of the alphabet; written document").
'Obliterate' literally means 'to strike out the letters' — from Latin 'oblitterāre' (to erase, to cause to be forgotten), from 'ob-' (against) + 'littera' (letter). To obliterate something was originally to cross out its written record. The destruction of text became the metaphor for the destruction of anything.