The term PRES. MONOGRAM is a reference to the three-letter monograms of the presidents of the United States. The crossword solutions for this term are DDE, JEC, and RMN, which stand for Dwight D. Eisenhower, John F. Kennedy, and Richard M. Nixon, respectively. Eisenhower was the 34th president of the United States, serving from 1953 to 1961. Kennedy was the 35th president, serving from 1961 to 1963. Nixon was the 37th president, serving from 1969 to 1974.