The crossword solution for the term SOUND FOR OLD MACDONALD is 'OINK', which is a four letter word. Oink is the sound that a pig makes, and is often associated with the popular children's song 'Old MacDonald Had a Farm'. The song is about a farmer named Old MacDonald who has various animals on his farm, including a pig, and the song includes the line 'with an oink oink here and an oink oink there'.