Final answer:
A grand manner portrait is a type of portrait painting that visually refers to classical art and culture of Ancient Greece or Rome. It aims to elevate the subject by depicting them in regal or dignified poses, often surrounded by symbols of power and status.
Step-by-step explanation:
A grand manner portrait is a type of portrait painting that aims to elevate the subject through various visual techniques. In the context of 18th-century works by Gainsborough, a grand manner portrait refers to a painting that visually refers to classical art and culture of Ancient Greece or Rome, as well as the artistic movements of Neoclassicism. These portraits often depict individuals in regal or dignified poses, surrounded by architectural settings or symbols of power and status.