yet
Yet is a common English word that can function as an adverb and as a coordinating conjunction. It is used to indicate time up to the present, to introduce a contrast or an unexpected development, or to begin a sentence in formal or literary contexts. It appears in fixed expressions such as as yet and yet again.
As an adverb, yet typically appears with negation or in questions. In negative sentences it means “up
As a conjunction, yet introduces a contrast or concession and is roughly equivalent to “nevertheless” or “but”
As yet and yet again are common phrases. As yet means “so far” or “up to this