| Uninteresting structural support? | 33 |
| Unintuitive thing for language learners | 39 |
| Union activist Norma ___ Webster | 32 |
| Union created by a 1955 merger, briefly | 39 |
| Union currently run by James P. Hoffa | 37 |
| Union for voice-over artists (FAR AT anagram) | 45 |
| Union founded by Samuel Gompers, for short | 42 |
| Union founded in 1886, for short | 32 |
| Union involved in recent GM negotiations | 40 |
| Union known for its health benefits? | 36 |
| Union member of the future: Abbr. | 33 |
| Union of the personal soul with God | 35 |
| Union organizer Jimmy who disappeared | 37 |
| Union Pacific or Greyhound stop (abbr.) | 39 |
| Union Pacific Railroad headquarters | 35 |
| Union Pacific's headquarters | 32 |
| Union prison site in NW Illinois | 32 |
| Union that doesn't charge dues | 34 |
| Union that merged with SAG in 2012 | 34 |
| Union tune sung by Baez at Woodstock | 36 |
| Union whose largest locals are in L.A. and N.Y.C. | 49 |
| Union with 3+ million members, in brief | 39 |
| Union with a Dropout Prevention center | 38 |
| Union ___ (Dow Chemical subsidiary) | 35 |
| Unique ancient tongue of SW Europe | 34 |
| Unique button in 007's Aston Martin | 39 |
| Unique feature of the Green Bay Packers | 39 |
| Unique identifier using the five vowels | 39 |
| Unique numbers assigned to websites | 35 |
| Unisex fragrance introduced in 1996 | 35 |
| Unisex name meaning "born again" | 42 |
| Unisex wraparound skirt of Polynesia | 36 |
| Unit a little longer than an arm's length | 45 |
| Unit equal to 100,000,000 maxwells | 34 |
| Unit equal to 61.02 cubic inches | 32 |
| Unit equal to one billion gammas | 32 |
| Unit equal to one candela per square meter | 42 |
| Unit equal to one coulomb per second | 36 |
| Unit equal to one millionth of a meter | 38 |
| Unit equaling 10,000 square meters | 34 |
| Unit equivalent to 3.26 light years | 35 |
| Unit equivalent to 550 foot-pounds per second | 45 |
| Unit for measuring flow of light | 32 |
| Unit from the Greek for "work" | 40 |
| Unit having two or more battalions | 34 |
| Unit in a "Mary Poppins" song | 39 |
| Unit in a terrorist organization | 32 |
| Unit in measuring population density | 36 |
| Unit in the definition of surface tension | 41 |
| Unit inserted through the vagina, briefly | 41 |
| Unit named after the inventor of the telephone | 46 |
| Unit named for a French physicist | 33 |
| Unit named for a telephone pioneer | 34 |
| Unit of ammo for a werewolf hunter | 34 |
| Unit of capacity (2150.42 cu. in.) | 34 |
| Unit of currency in the Harry Potter books | 42 |
| Unit of currency replaced by the kwanza in Angola | 49 |
| Unit of electric current, informally | 36 |
| Unit of energy (not power or time) | 34 |
| Unit of length equal to 1,760 yards | 35 |
| Unit of linear or square measure | 32 |
| Unit of meas. that's often leveled | 38 |
| Unit of measure equal to 63 gallons | 35 |
| Unit of refractive power of a lens | 34 |
| Unit of storage capacity, informally | 36 |
| Unit on a space vehicle, for short | 34 |
| Unit rendered obsolete by computer animation | 44 |
| Unit represented by an upside-down omega | 40 |
| Unit scrimmaging against the starters | 37 |
| Unit slightly larger than a joule: abbr. | 40 |
| Unit that's larger than 19 trillion miles | 45 |
| Unit that's the reciprocal of an ohm | 40 |
| Unit tracked by the Nikkei Index | 32 |
| Unit used in expressing salaries | 32 |
| Unit used in measuring wire diameters | 37 |
| Unit used to measure a city's area: abbr. | 45 |
| United (with ''up'') | 36 |
| United Arab Emirates' capital | 33 |
| United Arab Republic member, once | 33 |
| United entities before 1991: Abbr. | 34 |
| United hub on the West Coast, briefly | 37 |
| United Kingdom territory until 1957 | 35 |
| United Kingdom's Guy __ Night | 33 |
| United Kingdom, our # _____ trader | 34 |
| United Nations cofounder Charles | 32 |
| United Nations headquarters decoration | 38 |
| United Nations member since 1993 | 32 |
| United Nations member since 2002 | 32 |
| United Nations observances since 1950 | 37 |
| United Nations Secretary General, once | 38 |
| United States Army Infantry School site | 39 |
| United States Constitution's first article | 46 |
| United States Department of Defense headquarters | 48 |
| United States government, per Khomeini | 38 |
| United States military decoration | 33 |
| United States observance of April 14 | 36 |
| United States Postal Service cartoon character | 46 |
| United States Postal Service symbol | 35 |
| United States' second-smallest state capital | 48 |
| United States, our # ____ trader | 34 |