Which of the following best defines a 'sentence'?

The definition of a 'sentence' is best captured by the option that describes it as a group of words that typically expresses a complete thought. This encompasses the essential elements of a sentence, which include a subject and a predicate, allowing it to communicate a complete idea. A well-formed sentence provides clarity and context, helping to convey information effectively.

In contrast, a group of words that solely expresses a thought without forming a complete statement lacks the necessary structure to be classified as a proper sentence. Similarly, if a group of words is missing either a subject or a verb, it cannot be considered a complete sentence, as it does not provide sufficient information to convey a clear idea. Lastly, a single word, while it may hold meaning, does not fulfill the criteria of a sentence since it does not consist of a structured group of words. This structural integrity is what ultimately defines a sentence.