1) An introductory paragraph 2) Elementary 3) Foundation 4) Opening 5) Preliminary 6) Serving or used to introduce 7) Serving to open or begin 1) First 2) Inductive 3) Initial 4) Initiative 5) Initiatory 6) Opening 7) Preceding 8) Prefatorial 9) Prefatory 10) Prelusive 11) Prolegomenous 
• (a.) Serving to introduce something else; leading to the main subject or business; preliminary; prefatory; as, introductory proceedings; an introductory discourse.
In`tro·duc'to·ry adjective [ Latin itroductorius : confer French introductoire .] Serving to introduce something else; leading to the main subject or business; preliminary; prefatory; as, introductory proceedings; an introductory discourse. 
[adj] - serving to open or begin 2. [adj] - serving as an introduction or preface
introductory Serving or used to introduce; preliminary; beginning: 'The professor presented his introductory course in linguistics.'
adjective serving as a base or starting point; `a basic course in Russian`; `basic training for raw recruits`; `a set of basic tools`; `an introductory art course`prefatorial adjective serving as an introduction or preface
serving or used to introduce; preliminary; beginning: an introductory course; an introductory paragraph.