Esports, along with other gaming-related words such as permadeath and completionist, are among dictionary.com's newest additions.
Over the past few years, esports have been steadily gaining notoriety, not just in hardcore gaming circles, but among the general public. From tournaments that cover your college tuition to tournaments that pack a 40,000-person capacity soccer stadium, esports have essentially become an everyday part of life. Just like, you know, real sports. To recognize this, dictionary.com has named "esports" as one of its thousand new words of 2015.
It is defined as: "competitive tournaments of video games." But esports wasn't the only gaming-related word to gain legitimacy, as other additions included "completionist" (a player who attempts to complete every challenge and earn every achievement or trophy in a video game) and permadeath (the permanent death of a defeated character, after which the player of the game cannot continue with the same character).
There were also quite a few "geek culture" additions, like dox (to publish the private personal information of (another person) without the consent of that individual), lifehack (a tip, trick, or efficient method for doing or managing a day-to-day task or activity) and "ship" (to take an interest in a romantic relationship between fictional characters or famous people).
Dictionary.com is primarily based off the Random House Webster's Unabridged Dictionary. It adds words dependent on how often they're used, along with other factors such as search frequency.
So there we ago. Another point in favor of those of us who are constantly arguing that esports is just as legitimate as real sports.