An amusement park was, according to Spock, "an old Earth name for a place where people could go to see and do all sorts of fascinating things."
The Shore Leave Planet was likened to an amusement park because it was a planet constructed for people to come and play. All an individual had to do here was imagine their fondest wishes, old ones they wished to relive or new ones, ranging from fear, love, and triumph. (TOS: "Shore Leave")
Upon re-visiting this planet in 2269 and coming under attack with the rest of the landing party, Spock commented that "our amusement park no longer seems content to amuse." (TAS: "Once Upon a Planet")
In 2376, when Seven of Nine and Tuvok went on an away mission during recreational shore leave, B'Elanna Torres commented that, "The Borg wouldn't know fun if they assimilated an amusement park". (VOY: "Tsunkatse")