An anagram is a type of word play, the result of rearranging the letters of a word or phrase to produce a new word or phrase, using all the original letters exactly once; e.g., orchestra = carthorse, A decimal point = I'm a dot in place, Tom Marvolo Riddle = I am Lord Voldemort. Someone who creates anagrams is called an anagrammatist. The original word or phrase is known as the subject of the anagram.
Any word or phrase that exactly reproduces the letters in another order is an anagram. However, the goal of serious or skilled anagrammatists is to produce anagrams that in some way reflect or comment on the subject. Such an anagram may be a synonym or antonym of its subject, a parody, a criticism, or praise; e.g. George Bush = He bugs Gore; Madonna Louise Ciccone = Occasional nude income or One cool dance musician; William Shakespeare = I am a weakish speller, Roger Meddows-Taylor = Great words or melody. Anagrams are also often used in fiction for character aliases, such as Tom Marvolo Riddle = I Am Lord Voldemort.

en.wikipedia.org/wiki/Anagram