| One "a-leaping" in a Christmas song | 45 |
| One 'twixt 12 and 20 | 24 |
| One ''A'' in Paris | 34 |
| One ___ (sandlot game) | 23 |
| One to Juan | 12 |
| One in Paris | 13 |
| One in Oaxaca | 14 |
| One in Essen | 13 |
| One in Bonn | 12 |
| One in Berlin | 14 |
| One in Arles | 13 |
| One | 3 |
| Oncoming | 8 |
| Oncology procedure | 18 |
| Oncologist's suggestion | 27 |
| Oncologist's suffix | 23 |
| Oncle's wife | 16 |
| Oncle's spouse | 18 |
| Oncle's relative | 20 |
| Oncle's partner | 19 |
| Oncle's mate | 16 |
| Oncle's counterpart | 23 |
| Once: Lat. | 10 |
| Once: Ger. | 10 |
| Once/a time go-between | 22 |
| Once-___ (quick examinations) | 29 |
| Once-___ (quick appraisals) | 27 |
| Once-worshipped white wader | 27 |
| Once-worshiped white wader | 26 |
| Once-while link | 15 |
| Once-wedded ones | 16 |
| Once-ubiquitous shoe retailer | 29 |
| Once-ubiquitous black-on-yellow image | 37 |
| Once-trendy Hollywood workout routine | 37 |
| Once-stylish footwear | 21 |
| Once-seedy section of NYC | 25 |
| Once-scandalous exposure | 24 |
| Once-sacred snakes | 18 |
| Once-sacred snake | 17 |
| Once-sacred slitherers | 22 |
| Once-sacred reptiles | 20 |
| Once-sacred coilers | 19 |
| Once-rare Sunday sights | 23 |
| Once-promising failures | 23 |
| Once-prominent Arby's competitor | 36 |
| Once-pricey flyers | 18 |
| Once-powerful republic of NW Italy | 34 |
| Once-popular street liners | 26 |
| Once-popular song | 17 |
| Once-popular Olds | 17 |
| Once-popular feather source | 27 |
| Once-popular diet soft drink, or part of the can | 48 |
| Once-popular diet | 17 |
| Once-popular computers | 22 |
| Once-popular coiffure | 21 |
| Once-popular children's TV character | 40 |
| Once-popular anesthetic | 23 |
| Once-over giver | 15 |
| Once-named | 10 |
| Once-mighty initials | 20 |
| Once-ler's foe | 18 |
| Once-in-a-lifetime trip, for some | 33 |
| Once-in-a-lifetime traveler | 27 |
| Once-in-a-lifetime pilgrimage | 29 |
| Once-in-a-lifetime exchange, maybe | 34 |
| Once-in-a-lifetime | 18 |
| Once-in-a-blue-moon events | 26 |
| Once-in-a-blue-moon | 19 |
| Once-hot demographic, casually | 30 |
| Once-homeless "Golden-Voiced" Williams | 48 |
| Once-gritty Big Apple neighborhood sometimes called Midtown West | 64 |
| Once-fearsome extinct cat | 25 |
| Once-fashionable tableware | 26 |
| Once-fashionable card game | 26 |
| Once-faddish aerobics regimen | 29 |
| Once-dominant industry in Pittsburgh | 36 |
| Once-divided place | 18 |
| Once-divided city | 17 |
| Once-common urban skyline sights | 32 |
| Once-common skyline sights | 26 |
| Once-common pesticide component | 31 |
| Once-common monochrome PC display | 33 |
| Once-common Georgia sights | 26 |
| Once-common desert fighting force | 33 |
| Once-common commercial fuel | 27 |
| Once-common childhood malady | 28 |
| Once-common childhood ailment | 29 |
| Once-common "commonly" | 32 |
| Once-called | 11 |
| Once-beautiful castle? | 22 |
| Once-autonomous people of southern Russia | 41 |
| Once-around-Sol period | 22 |
| Once-around | 11 |
| Once-again fashionable soulful rock instruments | 47 |
| Once-a-yr. purchases | 20 |
| Once-a-year visitor | 19 |
| Once-a-year travelers | 21 |
| Once-a-year celebrity | 21 |
| Once-a-year bloomer | 19 |
| Once-a-week menace | 18 |