Enter is the English language derivative of the French word entrée, referring to the first dish served as part of a meal. The word was originally used in its original form on restaurant menus up until the 1970s with the advent of Desk-top Publishing, which allowed hôteliers, restaurateurs and café owners to produce their own hideous clip-art, Comic Sans and typo-ridden literature.
Following a simple misspelling by John Brooks, a fast-food restaurant owner in New York, of the word "entrée" as "enter" (presumably he was following the simple rules of the English-American Dictionary), the error spread like wildfire. Most of John's clients worked in marketing, and propagated the new spelling across the English-speaking world within a matter of weeks.
Some typical enters served in restaurants: