Don's bulbs rare light bulbs and lamps glossary of terms definition of: AMERICAN NATIONAL STANDARD INSTITUTE What is AMERICAN NATIONAL STANDARD INSTITUTE? AMERICAN NATIONAL STANDARD INSTITUTE refers to ANSI. ANSI code is 3 letter bulb code assigned by the American National Standard Institute and is one of the main industry standard bulb codes. Other important industry standards are LIF and ECE. Industry standard codes assure mechanical and electrical interchangeability for various manufacturers. references for this page: ANSI, ANSI CODE, AMERICAN NATIONAL STANDARD INSTITUTE references to this page: ECE, LIF