1. Description of a word formed from the first (or first few) letters of a series of words: Examples formed in an acronymic way are radar, which comes from radio detecting and ranging, NATO, which comes from North Atlantic Treaty Organization, scuba, which comes from self-contained underwater apparatus, and sonar, which comes from sound navigation ranging.
2. Characteristic of words created from the initial letters of a phrase: Such acronymic examples are "Random Access Memory" which becomes RAM, pronounced as the word "ram", and the scientific term LASER that is a result of "Light Amplification by Stimulated Emission of Radiation".