The Three Words English Flattens to One
English has one everyday word for what happens when a person thinks: mind. Classical Buddhist philosophy, working in Sanskrit and Pali, used three: citta, manas, and vijñāna. All three get translated into English as mind, or sometimes thought, or consciousness, and the translation is not wrong exactly. It is just incomplete in a specific, documented way.
The Princeton Dictionary of Buddhism offers one way the terms were distinguished: citta is so named because it builds up, accumulating wholesome and unwholesome states over time. Manas is named for its function of calculating and examining. Vijñāna is named for its work of discriminating among sensory stimuli, sorting one sense impression from another. On this reading, the three words are not three separate things so much as three different jobs that a single activity, loosely called mind, is doing at once: accumulating, examining, sorting.
Other sources draw the line differently. In certain Abhidhamma distinctions, manas refers to mind taken as a whole, while citta names each individual, momentary step of a mental process, one instant of mind following another in sequence. Vijñāna, on this account, is one particular form that a citta can take, a single step within a larger procedural flow. Elsewhere, Pali-English dictionaries describe citta as the heart-mind, carrying the passionate, emotional register, set against manas as the more purely intellectual faculty that grasps mental objects. A separate interpretive tradition assigns the three terms to three points in time: manas to the past, citta to the future, vijñāna to the present moment.
The Yogācāra school went furthest, treating the three terms as naming genuinely different realities rather than different angles on one reality. In this model, citta refers to a foundational storehouse consciousness, ālaya-vijñāna, accumulating impressions beneath ordinary awareness. Manas names an afflicted mental domain prone to grasping and distortion. Vijñāna refers to the six specific types of cognitive awareness tied to the senses. Three names, in this framework, are not three facets of one mind. They are three separate structures, doing different work, sometimes in conflict with each other.
That multiple serious traditions, working within the same broad Buddhist textual inheritance, drew the boundary between these three words in three incompatible places is itself the finding worth sitting with. A single English sentence can say someone changed their mind. The vocabulary available to say the same thing in classical Sanskrit asks, first, which of three different things changed, and that question did not have one agreed answer even among people reading the same texts.