(1) In this Chapter -

"certificate of authorisation" means a certificate issued under section 531(11);

"certificates of deduction" has the meaning assigned to it by section 531(6)(f);

"certified subcontractor", in relation to a principal, means a subcontractor - (a) in respect of whom the principal holds, at the time of making a payment under a relevant contract to the subcontractor, a relevant payments card for the year in which the payment is made, and (b) in respect of whom the principal has not received a notice under paragraph (a) of subsection (13) of section 531;

"chargeable period" has the same meaning as in section 321(2);