A rebus is a puzzle in which a letter or group of letters, called the rubric, represents the word or phrase to be guessed. An example is TLARH = 'labrynth' (LA by R in TH). In a phonetic rebus, the sounds of the rubric play a part; for example, PK = 'puck' (P: you see K) or QT = 'cutie' (cu tie). In an enigmatic rebus, the letters as they stand are insufficient to give the answer, and something not shown must be assumed; for example, Q = 'one-tenth square mile', where the not-shown SUAREMILE plays a part in the answer. Other examples of rebi can be found in the May and November 1972 issues of Word Ways.
Cohen, P. M.
"Very Long Rebi,"
Word Ways: Vol. 7
, Article 4.
Available at: http://digitalcommons.butler.edu/wordways/vol7/iss4/4