The keyword "WhatsApp" functions primarily as a proper noun. It is the registered trademark and specific name of a freeware, cross-platform, centralized instant messaging and voice-over-IP service owned by Meta Platforms. As a proper noun, it refers to this unique entity, distinguishing it from other messaging applications.
However, due to its widespread adoption, the term has undergone a linguistic process known as anthimeria, or functional shift, allowing it to be used as other parts of speech. It is commonly used as a verb, meaning to send a message or communicate using the application (e.g., "I will WhatsApp you the details"). Furthermore, it can function as an adjective to modify another noun, describing something related to or occurring on the platform (e.g., "a WhatsApp group" or "a WhatsApp notification").
For the purpose of an article, identifying the main part of speech is crucial for establishing the core subject. While its verbal and adjectival uses are significant, they are derivative. Therefore, the foundational and most accurate grammatical classification for "WhatsApp" is as a proper noun, representing the specific application itself. The other uses illustrate the brand's cultural impact and integration into common parlance.
