Definition of the word does

The word "does" is a third-person singular present tense form of the verb "do." Its origins can be traced back to Old English, where it was spelled "dō" and used as both a main and auxiliary verb. The original meaning of "dō" in Old English included not only the sense of action or performance (as in "Tom does the dishes every night") but also the sense of being or existing (as in "The sun does shine today") and even being able to (as in "Dō maþelon thus" or "The Maiden thus can do"). As English evolved and grammar developed, "dō" split into two distinct words: "do" as a main verb (meaning "accomplish" or "perform an action," as in "Tom does cooking classes") and "do" as an auxiliary verb (meaning "be" or "have" in certain contexts, as in "The sun does shine today" or "Mary does not have a phone"). Over time, the use of "dō" as a form of "be" or "have" became more restricted, eventually being confined to negative or interrogative sentences (as in "She does not like spicy food" or "Does she have a car?") This usage of "does" as an auxiliary verb continues to this day in Modern English.