mental object vs matter

Other hyponyms of mental object include tradition, object, food, food for thought, intellectual nourishment, noumenon, thing-in-itself, universe, universe of discourse, issue, subject, topic, issue, idea, thought, center, centre, core, essence, gist, heart, heart and soul, inwardness, kernel, marrow, meat, nitty-gritty, nub, pith, substance, sum, wisdom, internal representation, mental representation, representation, belief, kenosis, disbelief, unbelief, heresy, unorthodoxy, end, goal, education, experience, acculturation, culture, lore, traditional knowledge, ignorance, domain, knowledge base, knowledge domain, metaknowledge.