The term 'SON OF DONALD' can be solved by the crossword solution 'ERIC', which is a four letter word. Eric is a common given name in English-speaking countries, derived from the Old Norse name Eiríkr. It is also the name of several characters in Norse mythology, including the son of King Hálfdan and the son of King Ragnar Lodbrok. In modern times, it is most commonly associated with Eric Trump, the third child and second son of President Donald Trump.