For your reference, here are the definition of inventor in Patent law and rules:
35 U.S.C. 116 Inventors.
When an invention is made by two or more persons jointly, they shall apply for patent jointly and each make the required oath, except as otherwise provided in this title. Inventors may apply for a patent jointly even though (1) they did not physically work together or at the same time, (2) each did not make the same type or amount of contribution, or (3) each did not make a contribution to the subject matter of every claim of the patent.
§ 1.45 Joint inventors.
(a) Joint inventors must apply for a patent jointly and each must make the required oath or declaration:
neither of them alone, nor less than the entire number, can apply for a patent for an invention invented by them jointly, except as provided in § 1.47.
(b)
Inventors may apply for a patent jointly even though
(1)
They did not physically work together or at the same time,
(2)
Each inventor did not make the same type or amount of contribution, or
(3)
Each inventor did not make a contribution
to the subject matter of every claim of the application.
(c)
If multiple inventors are named in a nonprovisional
application, each named inventor must have made a contribution, individually or jointly, to the subject matter of at least one claim of the application and the application will be considered to be a joint application under 35 U.S.C. 116. ...