The term "Grand manner" is not widely recognized as an established concept in academic or encyclopedic sources. It may be interpreted as a phrase derived from art history or literary criticism, where "grand manner" (sometimes "grand style") traditionally refers to a dignified, elevated mode of expression or representation, particularly in painting, rhetoric, or literature. In 18th-century British art, for instance, the "grand manner" denoted a style of portraiture or historical painting that employed classical ideals, heroic themes, and formal composition to convey nobility and moral virtue, as practiced by artists like Sir Joshua Reynolds.
However, as a defined term "Grand manner" does not appear in authoritative reference works with a standardized or distinct meaning. Accurate information is not confirmed. The capitalized form "Grand manner" may suggest a specific usage, but no reliable sources validate such a designation. Without verifiable context or scholarly recognition, the term remains ambiguous and cannot be authoritatively described beyond speculative or contextual interpretation.