Why is the name of Jurassic Park movie wrong?

The name of the movie "Jurassic Park" is not technically wrong, but it refers to the theme park in the franchise rather than the time period. The time period depicted in the movies is actually the Cretaceous period, which is the last period of the Mesozoic era and lasted from around 145 million years ago to 66 million years ago. The Jurassic period came before the Cretaceous period and lasted from around 201.3 million years ago to 145 million years ago.