The word “letter” has a long and sophisticated history. Its origins can be traced back to the Latin word littera, which means “letter of the alphabet.” This eventually led to the Old English word letter, which referred to both letters of the alphabet and written documents.
Over time, the meaning of the word shifted slightly and came to refer specifically to written documents. Today, we use letter primarily in reference to personal correspondence or official communications.
Interestingly, this is not the only meaning of littera. In ancient Rome, a littera was also a unit of measurement equivalent to about one-third of an ounce (or just over 10 grams). This usage persists in some modern languages; in Italian, for example, la libbra (pound) is still divided into 16 once (ounces), each further subdivided into 12 lire (pennies).