Mawson, C.O.S., ed. (1870–1938). Roget’s International Thesaurus. 1922.

Class IV. Words Relating to the Intellectual Faculties
Division (I) Formation of Ideas
Section I. Operations of Intellect in General

450. Intellect.

   NOUN:INTELLECT, mind, understanding, reason, thinking principle; rationality; cogitative -, cognitive -, discursive -, reasoning -, intellectual- faculties; faculties, senses, consciousness, observation, percipience or percipiency, apperception, mentality, intelligence, intellection [obs.], intuition, association of ideas, instinct, conception, judgment, wits, parts, capacity, intellectuality, genius; brains, cognitive -, intellectual- powers; wit [See Intelligence. Wisdom]; ability (skill) [See Skill]; wisdom [See Intelligence. Wisdom]; Vernunft [Ger.], Verstand [Ger.].
  EGO, soul, spirit, ghost [archaic], inner man, heart, breast, bosom, penetralia mentis [L.], divina particula aurœ [L.], anima divina [L.], heart’s core; psyche, pneuma, subconscious self, subliminal consciousness, supreme principle, the Absolute.
  SEAT OF THOUGHT, organ of thought, sensorium, sensory, brain; head, head-piece; pate [colloq.], noddle [colloq.], skull, pericranium, cerebrum, cranium, brain pan, brain box, brain case, sconce [colloq.], upper story [colloq.].
  [SCIENCE OF MIND] metaphysics; philosophy [See Thought]; psychics; pneumatology, psychology, psychogenesis; noölogy, noöscopics, ideology; mental -, moral- philosophy; philosophy of the mind.
  phrenology; craniology, cranioscopy; psychometry, psychophysics, psychanalysis or psycho-analysis.
  IDEALITY, idealism; transcendentalism, immateriality [See Immateriality]; universal -concept, – conception; mahat [theos.].
  PSYCHICAL RESEARCH; telepathy, thought transference, thought reading; clair-audience; clairvoyance, mediumship; spiritualism [See Psychical Research]
  metaphysician, philosopher, psychologist, psychometer, psychopath, psychophysicist; psychic, medium, spiritist; adept, mahatma, yogi [Hinduism].
   VERB:REASON, understand, think, reflect, cogitate, excogitate, conceive, judge, contemplate, meditate; ruminate (think) [See Thought].
  NOTE, notice, mark; take -notice, – cognizance- of; be aware of, be conscious of; realize; appreciate; fancy (imagine) [See Imagination].
   ADJECTIVE:[RELATING TO INTELLECT] intellectual, mental, rational, endowed with reason; subjective, noöscopic, psychological; cerebral; percipient, appercipient, animastic; brainy [colloq.].
  HYPERPHYSICAL, superphysical; subconscious, subliminal; telepathic, clairaudient, clairvoyant; psychic or psychical, spiritual, ghostly; metaphysical, transcendental.
  IMMATERIAL [See Immateriality].
  1. Cogito ergo sum; ens rationis; frons est animi janua.—Cicero
  2. Locos y niños dicen la verdad; mens sola loco non exulat.—Ovid
  3. My mind is my kingdom.—Campbell
  4. Stern men with empires in their brains.—Lowell
  5. The mind, the music breathing from her face.—Byron
  6. Thou living ray of intellectual Fire.—Falconer
  7. The mental condition of the modern world … the condition in which all natural explanations have broken down and no supernatural explanation has been established.—Chesterton
  8. Friends, fellow mortals, bearers of the ghost That burns, and breaks its lamp, but is not lost.—Masefield