“Collateral Material is any company or product marketing pieces that are distributed directly to individual customers or can be viewed by customer in person. Examples are, brochures, cards, or displays that may be used in a sales meeting, sent by mail (if mailable) as a request for information, or displayed at a point of sale.” Via Level 10 Design

“Ancillary material used to support and reinforce a media advertising campaign such as sales kits, technical specification sheets, presentation charts, news releases, letters, films, catalogs, booklets, trade show exhibits, point-of-purchase displays (see point-of-purchase advertising), and annual reports.” Via Answers.com