Crawler vs Scrapper vs Parser(Grabber) vs Spider?

Question

Crawling

What, how and when to apply?
I did something like a parser that parses links, then a parser that parses a site. You specify a link to the site, and it collects the data you need in depth from the links.
Then there are all sorts of Spider, Scrapper and of course Crawler.
So the question arose, what and when to apply? How do Spider, Scrapper, Crawler work and what are the differences?
After all, they all have similar goals. In my situation, there is a site that needs to collect a specific ifna from other sites, which is better and why?

Answer 1

The scraping process begins with a spider that lazily (or purposefully) walks through sites, crawls html (saves html) and gives it to the html parser for parsing