Backlinks are links from another website to yours. These can be one way links or reciprocal links. These are one of the ways that search engines find out how popular you are, if you have a lot of backlinks it is a bit like youy are in the address books of a lot of people. It also matters how important those people are, but we won;t go into that now or you will think I'm a snob.
Black hat SEO refers to techniques that are frowned upon by search engines to get you higher in their ranks. One example from many moons ago that I witnessed was a website that reproduced the entire oxford english dictionary at the foot of their page in whited out text. This was soon discovered and they were duly banned from the major search engines. We avoid these techniques because they are not good for your business...but you have to know what to avoid, which is where experience counts.
Blog is short for 'weblog', or the online musings of various people. They figured highly in some search engine calculations until this method of promotion was abused.
Ecommerce websites that offer online sales use ecommerce, like this one over here,one of mine as it happens, which has a backlink now because of that plug.
A word that you target for emphasis in your website. If you sell widgets widget would be an important keyword to you.
If 'widget' is a keyword, 'blue widgets london' would be a keyphrase.
When you decide that you want to figure highly for certain keyphrases it is tempting to 'stuff' your page text until you have nothing but top heavy text. We must be aware that humans read this text and that search engines have clever algorithms that check for this.
SEO techniques on the site itself.
External things like backlinks or article marketing that might affect your sites SERPS
Google decided to rank web pages so you might have some idea as to the usefulness of these pages to you.
The art of optimising your website to appeal to search engines resulting in higher SERPS. Spelled 'search engine optimization' in the USA. (I put that in there just so I'd have both spellings in this text).
The page on the search engine that displays your results.
SEO techniques that are fully supported by the major search engines. Some techniques they tell you about, others you just have to guess. Experience is the key.