Here's a short story:

A stadium (plural stadiums or stadia) is a place or venue for (mostly) outdoor sports, concerts, or other events and consists of a field or stage either partly or completely surrounded by a tiered structure designed to allow spectators to stand or sit and view the event. 

Pausanias noted that for about half a century the only event at the ancient Greek Olympic festival was the race that comprised one length of the stade at Olympia, where the word "stadium" originated. In modern times, a stadium is officially a stadium when at least 50% of the actual capacity is an actual building, like concrete stands or seats. If the majority of the capacity is formed by grasshills, the sports venue is not officially considered a stadium. 

Most of the stadiums with a capacity of at least 10,000 are used for association football, or soccer, the most popular sport in the world. Other popular stadium sports include gridiron football, baseball, ice hockey, basketball, cricket, rugby union, rugby league, Australian football, Gaelic football, rugby sevens, field lacrosse, arena football, box lacrosse, futsal, minifootball, bandy, athletics, volleyball, handball, hurling, gymnastics, ski jumping, motorsports (formula 1, NASCAR, IndyCar, motorcycle road racing, motorcycle speedway, Monster Jam), wrestling, boxing, mixed martial arts, sumo, netball, tennis, table tennis, badminton, cycling, ice skating, golf, swimming, field hockey, Kabaddi, bullfighting, box lacrosse, international rules football, equestrianism, polo, horse racing and weightlifting. A large amount of large sports venues are also used for concerts. Basketball is the most popular arena (or indoor stadium) sport in the world. Large race circuits and large horse racing tracks are not stadiums, but sports venues, because the entire playing surface can't be seen from the stands. For the difference, compare List of stadiums by capacity with List of sports venues by capacity. (End of story)

Provide your best guess for the following question. Give ONLY the guess, no other words or explanation.

For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>

Here are a few examples of questions and answers:

Question: What is the standard?
Guess: \ a capacity of at least 10,000

Question: What are some of the uses?
Guess: gridiron football and baseball

Question: What is the plural form of the name?
Guess: stadiums

Question: Or?
Guess: stadia

Question: Who told about the ancient usage?
Guess: Pausanias

Question: How long was the race?
Guess: one length of the stade at Olympia

Now answer the following question in the same format.

Question: What word evolved from the length?

stadium