INTELLECTUAL
–adjective
1. appealing to or engaging the intellect: intellectual pursuits.
2. of or pertaining to the intellect or its use: intellectual powers.
3. possessing or showing intellect or mental capacity, esp. to a high degree: an intellectual person.
4. guided or developed by or relying on the intellect rather than upon emotions or feelings; rational.
5. characterized by or suggesting a predominance of intellect: an intellectual way of speaking.
–noun
6. a person of superior intellect.
7. a person who places a high value on or pursues things of interest to the intellect or the more complex forms and fields of knowledge, as aesthetic or philosophical matters, esp. on an abstract and general level.
8. an extremely rational person; a person who relies on intellect rather than on emotions or feelings.
9. a person professionally engaged in mental labor, as a writer or teacher.
10. intellectuals, Archaic.
a. the mental faculties.
b. things pertaining to the intellect.
INTELLECT
–noun
1. the power or faculty of the mind by which one knows or understands, as distinguished from that by which one feels and that by which one wills; the understanding; the faculty of thinking and acquiring knowledge.
2. capacity for thinking and acquiring knowledge, esp. of a high or complex order; mental capacity.
3. a particular mind or intelligence, esp. of a high order.
4. a person possessing a great capacity for thought and knowledge.
5. minds collectively, as of a number of persons or the persons themselves.
Minus the "on an abstract or general level" bit, this could apply to anyone who seeks knowledge.....myself included. I would not yet give myself the label of "intellectual", but I would consider labeling myself as being "in the pursuit of knowledge and wisdom, to the point of addiction".
So there you have it. I don't think that term is just for more abstract types of intelligence. (Slightly unrelated, but I got Intellectual as my 2nd "strength" in "Tom Rath's StrengthsFinder 2.0" book.)
I also read somewhere that ISTJs become "smarter," or "more valuable" with age, because the Si "hard drive of information" gets continually larger and more detailed with time. Cool, huh?