Medium screw base
Medium screw base means an Edison screw base identified with the prefix E-26 in the American National Standard for Electric Lamp Bases, ANSI_IEC C81.61-2003, published by the American National Standards Institute.
Source
10 CFR § 430.2
Scoping language
For purposes of this part, words shall be defined as provided for in section 321 of the Act and as follows -