The opening of “Entrapment,” with Sean Connery and Catherine Zeta-Jones, dominated the nation’s box office this weekend, earning an estimated $21.3 million from Friday to Sunday, studio sources said. The film set a record for best April opening ever, topping the $20.6 million mark set by “Life” two weeks ago. Elsewhere in the weekend box-office race, “The Matrix,” with Keanu Reeves, finished a distant second, with $8.7 million (giving the sci-fi thriller close to $130 million after 33 days). “Life” came in third with $6.4 million, followed by “Never Been Kissed” with $4.1 million. “Analyze This” finished fifth with $2.2 million.