What is mean by Google Ad-words? What are the latest Terminologies which we hear?

What is mean by Google Ad-words? 

Ad-words is the technique or the system which was designed by the Google in order to help the clients or users in marketing their products or services in SE which is Google search engine and also in the affiliate sites. By placing a text ad that appears on the SERP when people are searching for any  Query  /  Phrases that are related to our promoting product/services.
The terms or terminologies which we hear in Google Ad-words are as follows:

CPC - Cost per Click

CPM - Cost per Mile / 1000 Impressions(view)

CPA - Cost per Action / Acquisition.

CPS - Cost per Sale.

CPL - Cost per Lead.

CPR - Cost per Registration.

CPV - Cost per View

CTR -  Click-through rate.

CTR = ( No.of Clicks / Total Impressions ) *100 Minimum 2% of CTR is best for any business / services / products.

Ad placement:

	Ad Placement	Width	Height
Leaderboard	Header	728	90
	Footer	728	90
Large Skyscraper	SideBar	300	600
		150	465
		300	465
	Large Rectangle	336	280
	Medium Rectangle	300	250
		150	600
	Between the content	420	60
Horizontal Google Banner Ad Sizes	Large Leaderboard	970	90
	Banner	468	60
Vertical Google Ad Sizes	Skyscraper	120	600
	Wide skyscraper	160	600
Square Google Ad Sizes	Square	250	250
	Small square	200	200

These image sizes are called Ad Sizes in Ad-words, but whereas in the Affiliate program these image sizes are called the Banner Sizes.