The Grand Slam in professional golf is winning all of golf's major championships in the same calendar year.
The Grand Slam in men's golf is an unofficial concept, having changed over time. In the modern era, the Grand Slam is generally considered to be winning all four of golf's major championships in the same calendar year. Before The Masters was founded, the national amateur championships of the US and the UK were considered majors along with the two national opens; only Bobby Jones has ever completed a Grand Slam. No man has ever achieved a modern calendar year Grand Slam. Tiger Woods is the only golfer to hold a non-calendar year Grand Slam in holding all four titles together, winning all four consecutively (over two calendar years).
The term also refers to a tour tournament, the PGA Grand Slam of Golf, an annual off-season tournament contested by the winners of the four major championships.
In annual playing order, the modern major championships are:
The term "Grand Slam" was first applied to Bobby Jones' achievement of winning the four major golf events of 1930: The Open Championship, the U.S. Open, the U.S. Amateur and the British Amateur. When Jones won all four, the sports world searched for ways to capture the magnitude of his accomplishment. Up to that time, there was no term to describe such a feat because no one had thought it possible. The Atlanta Journal's O. B. Keeler dubbed it the "Grand Slam," borrowing a bridge term. George Trevor of the New York Sun wrote that Jones had "stormed the impregnable quadrilateral of golf." Keeler would later write the words that would forever be linked to one of the greatest individual accomplishments in the history of sports:
This victory, the fourth major title in the same season and in the space of four months, had now and for all time entrenched Bobby Jones safely within the 'Impregnable Quadrilateral of Golf,' that granite fortress that he alone could take by escalade, and that others may attack in vain, forever.