Any specific domain has their specific vocabulary, acronyms and other barriers to entry. We'll try to clarify anything too specific, from words beginners would fear to the ones experts still discover!
CTA: Call To Action - What you want the recipient of your ad to do after reading/watching.
CPC: Cost Per Click
CPM: Cost Per 1000 Impressions
CPA: Cost Per Action - for this one, remember that there are plenty of possible actions (Purchase, Click, Subscription, Add to Cart...). Just think of it as the end goal of your ad.
DA: Dynamic Ads
DAT: Dynamic Ads for Travel
Impression: An impression is a single display of a particular ad on a web page.
Ad Set: A group of ads that share the same daily or lifetime budget, schedule, bid type, bid info, and targeting data.
Conversion Funnel: The journey a consumer takes through an ad or search system, navigating an e-commerce website and finally converting to a sale. The funnel represents the way users are guided to the goal with fewer navigation options at each step.
An example would be: Impression > Click > Install > Register > View product > Add to Cart > Purchase.
Churn: Measure of the number of users/individuals who stopped using a product on a specified period.
Pixel: A Pixel is an invisible bit of code that would be embedded on your website. It usually collects some information about visitors and their behavior on the site. If you're interested in knowing how to set it up, you can learn more here.
Likes and Interests: Likes and Interests allows you to refine your ad's target audience based on what they've included in their profiles, as well as the Pages, groups and other things on Facebook they've connected with. This includes sections like interests, activities, favorite music, movies and TV shows.
Behavior: Similar to what Likes and Interests are, Behaviors are information on what a Facebook user probably likes, based on Pages he likes that are related to actual interests.
Custom Audience: Generally speaking, a Custom Audience is an ad targeting option that lets you find people who already know your business on Facebook. Using this option will let you use sources like customer lists, engagement data from Facebook or website/app traffic to create Custom Audiences.