Yes, these two terms both refer to the same marketing model, where advertisers pay a certain amount each time an ad of theirs is clicked. Paid search, PPC, Pay Per Click and search engine advertising are all interchangeable terms that refer to the same thing.

Cost per click (CPC) is a metric determined by various factors. The main factors are your quality score, maximum bid and the ad rank of competitors who bid for the same keywords.

Conversion Rate Optimisation is useful in all aspects of digital marketing. However, when it comes to CRO in PPC, by optimising your conversion rate, you can ensure that users not only land on relevant pages but by doing so are presented with all of the information they need.

The goal is for them to convert on that page, rather than leaving and potentially not converting (which would waste ad spend). The higher your conversion rate, the lower your cost per click, and cost per conversion, but your ads also generally receive higher positions in the SERP.

Negative keywords can be added to your Google Ads account to prevent your ads from showing for irrelevant queries within user searches, or to avoid crossover between ad groups and campaigns. For example, you may have one ad group for exact brand terms, and one for customer support. You would therefore want to add negative keywords for customer service-related terms to the specific campaign to avoid this showing to existing customers.