There are undoubtedly hundreds. A Rebus uses this technique, but is probably not the one you are thinking of. Show an example next time.
endsoz
3 letters are DIG in 479 that makes a word.
dozens
Dozens
under a mat
the word "valuner" rearranged makes the word "unravel"
Ruta is the Kikuyu word for the English word Subtract.
Those letters will spell percussion and supersonic.
Doornotgot
Just f makes the ffff sound, the other letters make up the first part of the word.
4 + 6 + 8 = 18 You've given us nineteen letters. It makes a difference. Either your word count is off, or your letters are incorrect.
Can you tell me what you call the process that makes one word from another word jumbling those letters - eg. LISTEN and SILENT? That is called an Anagram