It is the consonant eñe of the Spanish alphabet (among many) although it does not belong to the basic Latin alphabet. It is a double /N/ letter modified by medieval scribes and transcribers who used to combine letters to save space, since in words such as Latin annus ( "year") they placed one /n/ on the other, both of lower height ( / 8319;/ and / 8345;/ ) , which over time replaced with a /n/ or /N/ with a wavy or virgulilla line ( / 732;/ ) evoking the /n/ top. Since there is no general agreement on how to write, we can find old texts with an upper straight line ( / 8254;/ ) instead of the virgulilla, or this sign on the next vowel while omitting the /n/ that is over-denied. Today the /ñ/ is considered a letter and not a digraph or a combination with tildes, so when the EEC tried to remove it from the keyboards to uniformize its production and distribution in Europe, it was not possible.
