Short answer: No one knows for sure, but the term “love” is likely a French translation and the “15-30-40” point scoring system is probably a rehash of a previous games scoring system.
There’s no odder sports scoring system than the tennis scoring system. Love? 15-30-40? Really? What does it all mean?
What does “love” mean?
In sports, if you don’t score, it’s said you scored a “big ole goose egg.” Some believe a similar French term is the reason why having zero points in tennis is referred to as “love.” The French word, “l’ouef,” translates to egg so it makes sense that “l’ouef” slowly morphed into “love” over the years. The fact that tennis (likely) originated in 12th-century France makes this explanation seem even more plausible.
A less popular theory is based on the Dutch word, “lof,” which translates to honor. The thought is the player with zero (love) points is simply playing for honor because he/she certainly isn’t playing to win.
The “15-30-40” point scoring system
Before tennis was invented, the French played a similar game called, “jeu de pame” (palm game). Most experts believe the tennis scoring system was derived from this game. However, it’s not clear why “jeu de pame” used the “15-30-40” scoring system. Two theories seem reasonable to me.
The most popular theory is based on the “je de pame” court size. The court was 90 feet total, 45 feet per side. After scoring, the server would move forward 15 feet. Another score meant moving up another 15 feet. That’s 30 feet (get it?). Since a third score would put the player right up against the net, the final move was 10 feet (40).
The other theory is based on a 19th-century game called sphairistike. It was popular amongst the British officers stationed in India. The scoring system was based on the different gun calibers used by the British naval ships. When firing a salute, the ships first fired a 15-pound gun on the main deck, then a 30 pound gun on the middle deck, and finally a 40 pound gun on the lower deck.
Both of these seem plausible to me. Where do you think the tennis scoring system came from?