though

Though is a versatile word used primarily as a concessive conjunction and, in informal English, as a sentence adverb. As a conjunction, it introduces a subordinate clause that expresses a contrast with the main clause, roughly equivalent to although or even though: "Though it was late, they continued." It can appear at the start of a sentence or after the main clause, and the structure is common in both spoken and written English.

As a sentence adverb, though signals a contrast or concession and often appears at the end of a sentence: "It was expensive, though." In this position, it can soften a statement or acknowledge an exception. In formal writing, though is typically used in more casual or conversational style; for stronger concession, writers may choose even though or although.

Origins and usage notes: though derives from Old English þēah, a root shared with other West Germanic languages. In modern usage, though is distinguished from similar terms by its flexibility in position and tone. It should not be confused with other similarly spelled words such as thought (a noun or verb form) or through (a preposition or adverb with a different meaning).

In summary, though functions mainly as a concessive conjunction indicating contrast, while also serving as a discourse-friendly sentence adverb. Its informal tone and flexible placement make it a common tool for expressing nuanced relationships between ideas.