Which word means "with reference to" or "speaking of"?

The term "apropos" is derived from French and is used to indicate that something is relevant or appropriate to the matter at hand. When one says "apropos," it implies that there is a connection or relation to the subject being discussed. This makes it an ideal choice for expressing "with reference to" or "speaking of," as it signals that the forthcoming information is pertinent to the discussion.

In contrast, the other options do not convey the same meaning. "Adequate" refers to sufficiency or being enough for a particular purpose but does not imply any relevance to a specific topic. "Amicable" pertains to friendliness or goodwill during interactions and is unrelated to referencing or discussing a subject. "Anecdotal" relates to accounts or stories that may not be based on solid evidence, focusing more on narration than on the relevance to a specific topic. Thus, "apropos" stands out as the term that aligns directly with the concept of referencing or speaking about something.