Sure

Sure is a common English word used as an adjective, adverb, and interjection. As an adjective, it describes confidence or certainty about a statement, decision, or outcome, as in "Are you sure this is correct?" As an adverb, it signals strong affirmation or agreement, sometimes with a casual or emphatic tone, as in "That will surely work." In informal speech, sure can function as an interjection to grant permission or express willingness, for example "Sure, I can help." The word also appears in phrases such as "sure thing" or "sure enough."

Etymology: The term sure derives from Latin securus meaning "free from care, safe, secure" and entered English via Old French secur or seur in the Middle English period. The sense of certainty developed over time, paralleling related words like secure and surely.

Usage notes: Sure is versatile and context-dependent. It can moderate statements (Sure, I understand) or reinforce certainty (It's sure to rain). In some contexts, especially with a rising intonation, sure can be used sarcastically or insincerely, so tone matters. The related adverb surely is more formal for indicating inevitability or strong certainty.

Other uses: Sure is also a brand name for consumer products in multiple markets, notably a deodorant line marketed under the Sure brand in some regions. Brand applications do not imply any semantic relation to the word's linguistic senses.

See also: Yes, Affirmation, Certainty, Security, Surety.