The meaning of WHY is for what cause, reason, or purpose. How to use why in a sentence. We know that it’s due to increasing greenhouse gases from human activity. We also have tools that can help us better understand and better prepare for future climate change. So we develop computer models that help us understand how much it might change in the future. When we ask for reasons in speaking, we can use the phrase why is that? In informal conversations we often say why’s that?: … Learn the correct use of 'why do' vs 'why doing' with this clear, concise guide. Here, first 'does' shows a relation with the pronoun and then 'not' shows the relation with the pronoun and also with the verb 'does'. So, anything to be associated must follow the object or the subject and not preceded it. /waɪ/ IPA guide Other forms: whys Definitions of why noun the cause or intention underlying an action or situation, especially in the phrase `the whys and wherefores' synonyms: wherefore Earth rotates because of conserved angular momentum from its formation in a spinning disk of gas and dust. Inertia and lack of opposing forces maintain the rotation, causing the cycle of day and night. WHY definition: 1. for what reason: 2. used to express surprise or anger: 3. the reasons for something. Learn more. Easy Learning Spanish Grammar. Why do is used with plural subjects, while why does is used with singular subjects. Therefore, the choice between the two depends on the subject of the sentence.