An internet search engine is:

A site on the World Wide Web that has had search-bots scan other websites for various keywords, created an index (list) that includes what the easily available websites generally are about, and has a proprietary search engine (such as Google's, or Bing's, etc.) to check that indexed list of websites for which ones  include, somewhere, the search word(s) you're looking for.

An academic database is:

A collection of curated reliable digital information suitable for use by college and university students to find the content they need to succeed in their classes and attain their degrees.

They both have their uses, of course, but you don't search them the same way.

• Internet search engines 'interpret' what people type into their search boxes (because as we all know, people type all SORTS of things, including whole sentences), and usually bring back enough so you find something you can use.

• But Database search engines don't 'interpret' - they match. Because very item in that database is 'labeled' with information about it...what that database item is, what it's called, what it's about, where it came from, who made it, when they made it, who published it, etc. Due to this, databases can be seen as 'giant virtual filing cabinets'.

• So academic database search engines take your search words, and see if they can find a match with those 'labels' (aka: metadata) already on the items in the database.

• That's why the 'keywords' (those search words that really express your search's concepts) are so important while doing academic library research.