Google Search – Meaning of Grey Color in Synonyms

*EDIT: And looking further, it seems someone else has identified other sources so maybe my hypothesis doesn't hold. That article gives much better insight than I do. (The page is also 4 years old, but the most relevant post I could find.)

Doing a few random searches, it looks like all the answers come from the same sets of sources. My educated guess would be that Google has already determined sources which are trustworthy/reliable and have written algorithms to parse/search these resources and return these results in an order which is consistent with its other search algorithms.

I base this hypothesis on that I haven't seen any sources outside of these specific ones in approx 10 different searches:

• en.wikipedia.org/wiki/
• wordnetweb.princeton.edu/
• en.wiktionary.org/

This page offers some addditional suggestions on how to properly identify definitions in your HTML however the no conclusion was reach on how Google sources these definitions.

Here are two articles about changes Google has made to search which affect required terms. First Google started silently ignoring some of the search terms included in multiple term searches (making all search terms required by default was one of the reasons I originally liked Google better than Yahoo). Then more recently they stopped supporting the "+" to force term inclusion, apparently because they want to use that in searches involving Google+.

Google Just Made Bing the Best Search Engine

Google Kills Its Other Plus, and How to Bring It Back

In years past, I could have searched for things like the following and only gotten pages that had all these terms:

bengals highlights simpson

I would only double-quote exact phrases I wanted matched, such as "Cat on a Hot Tin Roof"

When I noticed the first change above several months ago, I started using the + operator, which had been previously redundant:

+bengals +highlights +simpson

Now it appears we have to separately double-quote each term we require which is a pain:

"bengals" "highlights" "simpson"