Merriam-Webster's Word of the Day for August 24, 2025, is the verb "cloister." To cloister means to shut someone or something away from the world. This is illustrated by a scientist cloistering himself in his laboratory to analyze data. A NASA administrator plans to cloister himself to write a book after stepping down. The word "cloister" entered English as a noun in the 13th century, referring to a convent or monastery. Later, it evolved into a verb meaning to seclude in or as if in a cloister. The noun can also describe monastic life or a covered passage around a court. The adjective "cloistered" means separated from the rest of the world. Ultimately, "cloister" derives from the Latin verb "claudere," meaning "to close." This Latin root also gives rise to words like close, conclude, and exclude.