In Vedic Sanskrit, the word 'Vastu' primarily means 'thing', 'object', 'material substance', or 'entity'. It is the root term for Vastu Shastra (science of architecture), but in its original Vedic context, it referred to material objects or dwelling things. Environment (B) refers to surroundings, antiques (C) are old collectibles, and rites (D) are ritual ceremonies.