始し新しん世せいししんせいMeanings1nounEocene epochGeological epoch from about 56 to 34 million years ago. Used in scientific and educational contexts.始し新しん世せいは、哺ほ乳にゅう類るいが大おおきく多た様よう化かした時じ代だいです。The Eocene epoch was a period when mammals diversified greatly.