Seoul automaker / MON 8-10-20 / Launch vehicle for many NASA missions / Bright sunny area of a house / Destination of rover Perseverance

THEME: KEYS (56D: Typically lost items that are "found" in the starts of 16-, 24-, 45- and 57-Across— first words of themers all have, or are associated with, KEYS:

Theme answers:

• ORGAN DONOR (16A: Designation on many a driver's license)
• FLORIDA ROOM (24A: Bright, sunny area of a house)
• ATLAS ROCKET (45A: Launch vehicle for many NASA missions)
• LOCK OF HAIR (57A: Ringlet on a salon floor)

Word of the Day: FLORIDA ROOM (24A) —

(US, Canada, especially East Coast US and Florida) A room within or adjoining a residence which is designed to admit considerable sunlight and fresh air, especially one which is not heated and is used only in the warmer seasons; a sunroom. (wikitionary)

Found this one actually slightly harder than your typical Monday puzzle, largely because none of the themers were obvious to me. Needed many crosses for all of them, even the hair, one (had OF HAIR, still wasn't sure what came first). Nothing in the ORGAN DONOR clue is very specific (lots of data on a driver's license). I think this may be the first time I've heard the term FLORIDA ROOM (though I did guess FLORIDA off just the -DA, so maybe it was in my brain somewhere). Don't pay very close attention to NASA missions so ___ ROCKET wasn't getting me anywhere either. I think the main problem was I backed into so many of these themers. Some kind of ROOM, some kind of ROCKET, something OF HAIR—that's what I encountered the first time I laid eyes on each of the last three themers. Just made things slower going than usual. Also found TROIKAS slightly hard to come up with (after TRIADS my brain blanked on other [Groups of three]). Same with PRAY DO (wow, "quaintly" is right, yikes) (35D: "Yes, proceed!," quaintly), and even BABY BONNET just wasn't coming quickly for me—even after I got the BABY part. What year is it that we're putting "wee ones" in "bonnets"? I think babies just wear sun hats now. Or ... we're just not putting babies in the sun, I don't know. I don't think Ella ever wore a bonnet. So ... Add in the inevitable hesitaiton created by 10D: Oodles (today, A LOT, some other day, A TON) and the fact that I had RAVING before RAHRAH (32A: Uncritically enthusiastic, colloquially), and you (I) have a solving time slightly north of average. That said, it's Monday, and it was easy. 

As for quality, I'm not too RAHRAH about the reveals, which is just KEYS and thus kind of a pfft. I see how they try to get cute with the whole lose your keys / "find" your keys conceit in the clue, but the lack of a good revealer makes plain old KEYS kind of sad. These are the days I wish the NYTXW had *titles* like the WSJ and Newsweek and most indies. A good title obviates the need for a revealer (if there's not hot revealer to be had). But sure, those first themer words are all things associated with KEYS. It's a good set, but FLORIDA ROOM clunks a bit, mostly because it's the only themer where that first word isn't completely reimagined by KEYS—that is, KEYS takes the organ from body organ to musical instrument organ, and takes Atlas from god ATLAS (I assume that's the basis of the rocket's name) to map atlas, and takes LOCK from hair unit to security item. But FLORIDA ROOM ... I assume tthe room is named after the state, and the KEYS are in the state, so there's no real redirection. FLORIDA is FLORIDA is FLORIDA. Plus I just don't know the term, so I'm already not inclined to *love* it. But mostly my problem is with the "Meaning Not Reimagined" part. The grid seems average. Old-fashioned, but clean enough, fine enough. Enough. 

Signed, Rex Parker, King of CrossWorld