Illustration of rebus
rebus
noun
re·bus ˈrē-bəs 
: a representation of words or syllables by pictures of objects or by symbols whose names resemble the intended words or syllables in sound
also : a riddle made up of such pictures or symbols
Did you know?
Rebus and a Lack of Words
A rebus communicates its message by means of pictures or symbols whose names sound like various parts of a word, phrase, or sentence. For example, a picture of a can of tomatoes followed by the letters UC and a picture of a well means "Can you see well?" In Latin, the word rebus means "by things"; rebus is a form of the Latin word res, which means "thing." English speakers started using the word rebus for picture writing in the early 1600s.
Example Sentences
Recent Examples on the Web Written in bits and bobs over the last two years, the emoji Haggadah was redrafted with each update of the emoji keyboard, and reads like a book-length rebus. 
Elisa Mala, New York Times, 6 Apr. 2020 Some contained complicated puzzles, acrostics, and rebuses (pictures that represent words or parts of words). Marilyn Yalom, Time, 14 Feb. 2018 The pointed wit card collection includes 100 cards, each with a nostalgic looking graphic with a printed word, similar to a rebus. Atlanta Life, ajc, 8 May 2017
Elisa Mala, New York Times, 6 Apr. 2020 Some contained complicated puzzles, acrostics, and rebuses (pictures that represent words or parts of words). Marilyn Yalom, Time, 14 Feb. 2018 The pointed wit card collection includes 100 cards, each with a nostalgic looking graphic with a printed word, similar to a rebus. Atlanta Life, ajc, 8 May 2017 Word History
Etymology
Latin, by things, ablative plural of res thing — more at real
First Known Use
1605, in the meaning defined above
Kids Definition
rebus
noun
re·bus ˈrē-bəs
: a riddle or puzzle made up of letters, pictures, and symbols whose names sound like the syllables and words of a phrase or sentence
I C U is a rebus.