Final answer:
Alfred Hitchcock first used a MacGuffin in the 1935 film 'The 39 Steps,' which involved the design for a silent airplane engine. The term describes an object that drives the plot, a concept he used in many of his films.
Step-by-step explanation:
Alfred Hitchcock popularized the term "MacGuffin" to depict an object that drives a film's narrative forward.
In the context of the question, the first significant usage of a MacGuffin by Hitchcock occurred in his 1935 film, which featured the design for a silent airplane engine.
The film in question is 'The 39 Steps', where the protagonist, played by Robert Donat, becomes embroiled in a spy thriller that centers around a stolen set of designs for this groundbreaking invention.
Although the concept of a MacGuffin was utilized by Hitchcock in many of his films, the reference to the lack of authentic Black characters pertains to another Hitchcock classic, 'Rear Window' (1954).
These films, despite their differences in plot and character development, remain influential pieces of cinema history.