The answer to the topic name ("What does elite mean?") is that "Elite" is a marketing term added to all but lowest Marriott Bonvoy membership tier. There is no difference between Gold and Gold Elite. Most participants on this forum don't bother to write two words when one word is sufficient.

The membership tiers are:

— Member (0-9 nights per year)
— Silver Elite (10-24 nights per year)
— Gold Elite (25-49 nights per year)
— Platinum Elite (50-74 nights per year)
— Titanium Elite (75-99 per year nights)
— Ambassador Elite (100+ nights plus USD$23K+ qualifying spend per year)

Members have benefits over non-members, such as earning points and getting free internet at properties that charge for internet. Benefits increase and improve with higher tiers. There's a big jump at the Platinum Elite level, when complimentary elite breakfast kicks in at many -- but not all -- Marriott Bonvoy brands, either as a Welcome Gift choice or as a function of Guaranteed Lounge Access (depending on the brand).

If you look at posts on this forum or reviews on TripAdvisor about Marriott legacy properties from before Marriott Awards and Starwood Preferred Guest were combined in 2018, you'll see references to free breakfast for Gold members. That's because the level that's now called Platinum (in Marriott Bonvoy) used to be called Gold (in Marriott Rewards). It's not an indication that Gold members still get free breakfast or that the program has gotten worse in this regard. It's just a name change to the tier for guests who achieved 50-74 qualifying nights per year.

It's worth reading at least the Marriott Bonvoy Benefits Overview marketing website. But you have to go to the Marriott Bonvoy Loyalty Program Terms and Condition for the specifics.