Above The Fold:- Any area of a web page that is viewable without the viewer having to use the vertical scroll bar. Ad space in this area is usually more expensive since it is more likely to be viewed by the visitor.

Banner: A graphic that appears on a web page that is usually hyperlinked to an advertisers web site. May be in a variety of formats including GIF, JPEG, Flash, HTML, Java, JavaScript and more.

Campaign:  The process of planning, creating, buying and tracking an advertising project from start to finish.

Call to Action (CTA):  An instruction often embedded in advertising that explains how to respond to an opt-in for a particular promotion.

Click Through Rate (CTR):  The percentage of impressions that resulted in a visitor. Calculated by dividing the number of clicks by the number of impressions.

Clicks:  The number of click throughs that have occurred as a result of a user clicking on a banner or ad and being redirected to an advertisers web page.

Cold Traffic:  Ad and website viewers that have not previously been exposed to the content.

Conversion: Term used to describe the process of getting a web visitor to accept an offer or become a paying customer. Advertisers strive for high conversion ratios.

CPC (Cost per click): is a popular way to purchase traffic. With this method of purchasing traffic the advertiser only pays for the traffic that goes to their website. This is an ideal method of payment for advertisers who need to guarantee they only pay for those surfers who click on the advertising link or banner and then go to their site.

CPM (Cost per thousand impressions): is one of the online payment models by which advertisers pays for every 1000 impressions of their advertisement.  This is an ideal method of payment for advertisers who want to focus on the number of people who see their banner. The "M" in CPM is from the Roman numeral for 1000. The Roman numeral M was derived from the latin word "mille" meaning "thousand".

Display ad:  also known as a banner ad, is a form of online paid advertising that is typically a designed image or a photo with some text.

Impressions:  are the number of times a banner or text ad was requested and presumably seen by users.

Keyword:  is a word or phrase entered into a search engine in an effort to get the search engine to return matching and relevant results. Many web sites offer advertising based on keyword targeting so an advertisers banner will only show when a specific keyword(s) are entered.

Landing Page:  is the page on a web site where one is taken after clicking on a advertisement. While this can be any page, it is often a page designed to expand on the service or product mentioned in the initial advertisement.

Opt In: - A process where by a user voluntarily agrees to start receiving email, usually commercial, about a topic of interest.

Pixel: refers to the tracking script that collects cookies of the users browser so that the user can be tracked and retargeted with banners. A conversion pixel is a tracking script that reports to the campaign when a conversion has taken place.

Retargeting:  a form of marketing used to find previous website visitors by using display banner ads to lead visitors back to the website. It is an effective marketing strategy that allows marketers to target users who have already been to your site and have experience with your brand or service.

Text Ad: an advertisement on the internet that contains words, often in a box, rather than a picture, and is usually linked to the website of the company advertising the product or service.

Sources:

http://www.onlineadvertising.net/glossary.html#J-terms

http://www.admedo.com/glossary-of-display-advertising

https://trackmaven.com/marketing-dictionary/display-ad/

http://dictionary.cambridge.org/dictionary/english/text-ad