What Is an Affirmative Sentence? – Meaning and Definition An affirmative sentence, as the name suggests, is a sentence structure that affirms a proposition, a day-to-day action, an idea, a request or a random thought. In simpler terms, it can be said that an affirmative sentence is a positive statement. The Oxford Dictionary of English Grammar defines an affirmative sentence as a sentence “stating that a fact is so; answering ‘yes’ to a question put or implied”. The Merriam-Webster ... The meaning of AFFIRMATIVE is asserting that the fact is so. How to use affirmative in a sentence. Meaning The term ‘affirmative’ refers to a positive response or assertion. It is commonly used in discussions, voting, and various forms of communication to indicate ‘yes’ or to confirm something. The essence of ‘affirmative’ is to express agreement or approval. Affirmative definition: affirming or assenting; asserting the truth, validity, or fact of something.. See examples of AFFIRMATIVE used in a sentence.