a person who gives lectures, esp. by profession or in connection with teaching duties: sometimes used as an academic title for one who teaches at a college or university but does not have the rank or tenure of a regular faculty member
See lecturer in American Heritage Dictionary 4
(lĕkˈchər-ər)
noun
One who delivers lectures, especially professionally.
a. A member of the faculty of a college or university usually having qualified status without rank or tenure.
b. A faculty member ranking below an assistant professor.
c. The academic rank held by such a faculty member.
Chiefly British A university teacher, especially one ranking next below a reader.