The everyday name for table tennis spent its early years as a brand. Several sources say that is why the sport's official name is table tennis.
NBC traces the game to wealthy Victorians in England, who made an indoor version of lawn tennis. It went through many names before one stuck. The same explainer lists whiff-whaff, pom-pom and clip-clap alongside ping-pong. J. Jaques & Son of London says it sold equipment in the 1890s under the name Gossima. Its own history admits that name lacked anything descriptive.
The winning name copied a sound. Etymonline calls Ping-Pong imitative of a ball striking a hard surface, pairing ping with pong. It records the word in 1900 as a Parker Brothers trademark for table tennis equipment. Other accounts differ. Wikipedia says the term was already in wide use when Jaques trademarked it in 1901. Jaques later sold the US rights to Parker Brothers.
The name took off fast. Etymonline describes a "phenomenal vogue" for the game in the United States from about 1900 to 1905. The verb, meaning to play the game, appeared by 1901.
Owning the name had a cost for everyone else. Wikipedia says other makers used the generic "table tennis" instead. The split even reached the sport's organizers. NBC reports that a Table Tennis Association formed in England in 1901, and a Ping Pong Association followed four days later. The two merged two years after that.
Parker Brothers enforced its trademark in the 1920s, and Wikipedia says that led various associations to rename themselves "table tennis." When the sport organized internationally in 1926, it chose the unbranded name. The International Table Tennis Federation was formed that year, and the first world championships followed.
The word kept moving after the game settled down. Etymonline dates the figurative verb, for sending something back and forth without progress, to 1952. It also says pong on its own was a clipped form of ping-pong by the late 1960s. The arcade video game Pong followed in 1972, taking just the second half of the sound.