Theme: Fill It Up - First word of the first four theme entries represents the descending levels of the unifier leaving just a drop at 66A.
18A. Ceremonial uniform : FULL DRESS
23A. Necktie knot : HALF-WINDSOR
38A. NCAA Elite Eight team : QUARTER-FINALIST. Between the Sweet Sixteen and the Final Four.
50A. Parent whose kids have moved out : EMPTY NESTER.
59A. Dashboard device, and a hint to the starts of 18-, 23-, 38- and 50-Across : FUEL GAUGE
66. What to add when the 59-Across gets low : GAS
Argyle here. Cute theme. 1-Across sets the level for the puzzle, I felt. Some of the cluing was dodgy. Neat how GAS fit under the GAUGE; that's when I buy gas.
Across:
1. Minister's home : MANSE
6. Inst. that turns out lieutenants : OCS. Officer Candidates School.
9. Poker game similar to Texas Hold 'em : OMAHA. Player receives four down cards instead of two but must play only two of them.
14. Polynesian greeting : "ALOHA"
15. Rock music's __ Fighters : FOO. Foo Fighters - Bridges Burning (Snippet)(0:30)
16. Tied, as shoes : LACED
17. Crest dispensers : TUBES. May have ADA on them.
20. Turf grabbers : CLEATS. Cartoon of a ball player, wearing cleats, making a shoestring catch.
22. Yo-yo string feature : LOOP
25. Tidal return : EBB
28. Ample shoe width : EEE
29. Temple with a minaret : MOSQUE. Image.
31. PC key for getting out of trouble : ESC
34. Way up : STAIR
37. Emanation detected by psychics, so they say : AURA
42. __ no good : UP TO
43. Kept secret : SAT ON
44. Faux __: blunder : PAS. May result in a "mea culpa".
45. Main thoroughfare : ARTERY
48. 41-Down sound in the comic "B.C." : "ZOT!". This guy. 41D. Threat to tiny workers : ANTEATER. This action.
49. __ of the land : LAY
57. Civil rights org. : ACLU. American Civil Liberties Union.
58. Work that ridicules folly : SATIRE
64. Carryalls : TOTEs
65. Out of port : AT SEA
67. Create, as a statute : ENACT
68. Back at the track : BET ON
69. The USA's 50 : STs. States
70. Takes in tenants : RENTS
Down:
1. Fire lighter : MATCH
2. Gene Vincent's "Be-Bop-__" : A-LULA. A significant early example of rockabilly. (2:35)
3. __ Prize : NOBEL
4. Grain bundle : SHEAF
5. How latitude lines run : EAST/WEST
6. On vacation : OFF
7. "This __ be the last time": Stones lyric : COULD. Clip(4:03)
8. Goes it alone : SOLOs
9. Rookie's mentor : OLD PRO
10. Make a dent in : MAR
11. Poker "bullet" : ACE
12. Bucks and rams : HEs
13. Commercials : ADs
19. Weaver's machine : LOOM
21. Seven, in Sinaloa : SIETE. Sinaloa is a Mexican state. Map.
24. Approaches : NEARS
25. Supply with gear : EQUIP
26. Sac between a bone and tendon : BURSA. Inflammation of a bursa is bursitis, most commonly of the shoulder.
27. Cop's rounds : BEATS
30. Gal of song : SAL. Clip.(1:08)
31. The same : EQUAL
33. Spiteful, as gossip : CATTY
35. "__ tree falls ..." : IF A. Did you hear that?
36. Swanky : RITZY
39. Fish eggs : ROE
40. High hours? : NOONS
46. '80s Cold War leader : REAGAN
47. Song spelled with arm motions : YMCA. No, no, no! No clip!
51. Spark providers : PLUGS. Barney Google and Spark Plug.
52. Pull on : TUG AT
53. Rosetta __ : STONE. Image. The Rosetta Stone is an ancient Egyptian stele inscribed with a decree issued in 196 BC. The decree appears in three scripts: the upper text is Ancient Egyptian hieroglyphs, the middle portion Demotic script, and the lowest Ancient Greek. Because it presents essentially the same text in all three scripts (with some minor differences between them), it provided the key to the modern understanding of Egyptian hieroglyphs.
54. Giant : TITAN
55. Standing upright : ERECT
56. Concludes one's court case : RESTS
59. Detergent brand : FAB
60. Jeep or Land Rover, briefly : UTE. Any type of utility vehicle.
61. Superlative suffix : EST
62. Lion sign : LEO
63. Dollar sign shape : ESS
Argyle
