Acronym
Part of speech: noun
Definition: An abbreviation formed by (usually initial) letters taken from a word or series of words, and which is itself pronounced as a word, such as RAM, radar, or scuba; sometimes contrasted with initialism. A pronounceable word formed from the beginnings (letter or syllable) of other words and thus representing the phrase so formed, e.g. Benelux = the countries Belgium, Netherlands and Luxembourg considered as a political or economic whole. Any abbreviation so formed, regardless of pronunciation, such as TNT, IBM, or XML.
Acrostic
Part of speech: noun
Definition: A poem or other text in which certain letters, often the first in each line, spell out a name or message.A particular kind of word puzzle: its solutions form an anagram of a quotation, and their initials often form its author.