47 C.F.R. §76.225
Commercial matter means air time sold for purposes of selling a product or service and promotions of television programs or video programming services other than children's or other age-appropriate programming appearing on the same channel or promotions for children's educational and informational programming on any channel.
Note 2 to § 76.225 : For purposes of this section, children's programming refers to programs originally produced and broadcast primarily for an audience of children 12 years old and younger.
Note 3 to § 76.225 : Section 76.1703 contains recordkeeping requirements for cable operators with regard to children's programming.