The widespread, frequent use of acronyms across the whole range of registers is a relatively new linguistic phenomenon in most languages, becoming increasingly evident since the mid-20th century. As literacy rates rose, and as advances in science and technology brought with them a constant stream of new (and sometimes more complex) terms and concepts, the practice of abbreviating terms became increasingly convenient. The "Oxford English Dictionary" ("OED") records the first printed use of the word "initialism" as occurring in 1899, but it did not come into general use until 1965, well after "acronym" had become common.