In the opening chapter of the novel, a couplet is introduced:
- Truth becomes fiction when the fiction's true;
- Real becomes not-real where the unreal's real.
As one critic points out, the couplet signifies "not a hard and fast division between truth and falsity, reality and illusion, but the impossibility of making such distinctions in any world, fictional or 'actual.'" The name of the main family, Jia (賈, pronounced jiǎ), is a homophone with the character jiǎ 假, meaning false or fictitious; this is mirrored by another family that has the surname Zhen (甄, pronounced zhēn), a homophone for the word "real" (真). It is suggested that the novel's family is both a realistic reflection and a fictional or "dream" version of Cao's own family.
The novel is most often titled Hóng Lóu Mèng (紅樓夢), literally "Red Chamber Dream". "Red chamber" is an idiom with several definitions; one in particular refers to the sheltered chambers where the daughters of prominent families reside. It also refers to a dream in Chapter 5 that Baoyu has, set in a "red chamber", where the fates of many of the characters are foreshadowed. "Chamber" is sometimes translated as "mansion" because of the scale of the Chinese word "樓". However the word "mansion" is thought to neglect the flavour of the word "chamber" according to scholar Zhou Ruchang.
The novel also provides great insight in its depiction of the Chinese culture of the time, including description of the era's "manners, expectations, and consequences." Many aspects of Chinese culture, such as medicine, cuisine, tea culture, proverbs, mythology, Confucianism, Buddhism, Taoism, filial piety, opera, music, painting, classic literature and the Four Books, are vividly portrayed. Among these, the novel is particularly notable for its grand use of poetry.