Acronym (from Greek. άκρος — highest, extreme + όνυμος — name) — type of abbreviation formed by initial sounds. Actually, an acronym is a word which is abbreviation that can be pronounced together (unlike abbreviations, which says "by letters").
The Americans and the British often use such abbreviations in the correspondence by SMS or Mail. Very interesting to read these acronyms because some of them we use in everyday life. Once the acronym is firmly "embedded" in the language, most people forget and don't even think about that, from what he is. Who today remembers what does the term "laser" (the laser)? So: "Light Amplification by Stimulated Emission of Radiation", i.e. "light amplification by stimulated emission".