Merriam-Webster's Word of the Day for October 5, 2026 is "perseverate," a verb. To perseverate means to intensely focus one's attention on a thought or thoughts. It can also mean to recur or repeat continually. The provided examples illustrate focusing on past regrets and nervous thoughts recurring. One example shows how people often focus on a significant loss rather than similar wins. Interestingly, the noun "perseveration" is older than the verb "perseverate." Psychologists adopted "perseveration" from German in the early 1900s. It described the act of repeating a behavior, like a verbal repetition. Later, scientists created the verb "perseverate" by altering the noun's suffix. This allowed for a verbal form of the repetitive action. "Perseverate" has since broadened its meaning in English.