We all know that you make an acronym by taking the initial letters of a set of words and putting them together. So Random Access Memory becomes RAM, or the United States becomes the US. But I only found out recently that these two examples are actually different.
An acronym is when the initials of a set of words are said as a word, like ram, laser, radar, sonar, Nato, or NASA. An initialism is where a set of initials are spelled out as letters when saying them, like FBI, CIA, USA, BBC, or CD.
HT: Jon Hoare