| Mk | Entry | Card | Episode |
| Ubean prison. | 101.1C | Fair Trade. [VGR] | |
| Ufandi III. | 003.3zKK.[D | Firstborn. [TNG] | |
| Ufandi III. | 101.1D | Firstborn. [TNG] | |
| UFO. | 101.1A | Tomorrow Is Yesterday. [TOS] | |
| Ugly Bags of Mostly Water. | 069.016-a | Home Soil. [TNG] | |
| Ugly Bags of Mostly Water. | 101.1E | Home Soil. [TNG] | |
| UHC card. | 101.1B | Past Tense, Part I. [DS9] | |
| Uhlan. | 101.1F | Unification, Part II. [TNG] | |
| Uhnari, Lieutenant Aquiel. | 043.096. | Aquiel. [TNG] | |
| Uhnari, Lieutenant Aquiel. | 101.1G | Aquiel. [TNG] | |
| \ | Uhura (mirror). | 041.1A.[J | Mirror, Mirror. [TOS] |
| Uhura. | 020.01M.[H | Corbomite Maneuver, The. [TOS] | |
| Uhura. | 043.009. | Corbomite Maneuver, The. [TOS] | |
| Uhura. | 101.1H | Corbomite Maneuver, The. [TOS] | |
| Uhura. (index) | 001.028. | Corbomite Maneuver, The. [TOS] | |
| Uhura. (communications officer) | 043.009A | ||
| Uhura. (Cultural difference) | 007.03A[B.a | Corbomite Maneuver, The. [TOS] | |
| Uhura. (Easily adaptable) | 043.009A[A | Star Trek IV: The Voyage Home. | |
| Uhura. (hands) | 068.72-a1 | Lights of Zetar, The. [TOS] | |
| Uhura. (memory restoration) | 068.36-a | Changeling, The. [TOS] | |
| Uhura. (Scotty) | 076.5-b | Star Trek V: The Final Frontier. | |
| Uhura. (siren dance) | 076.3-b | Star Trek V: The Final Frontier. | |
| Uhura. (Through thick and thin) | 043.009[A.a | Star Trek: The Motion Picture. | |
| Uhura. (Through thick and thin) | 043.009[A.b | Star Trek IV: The Voyage Home. | |
| Uhura. (Through thick and thin) | 043.009[A.c | Star Trek VI: The Undiscovered Country. | |
| Ulani Belor. | 101.1I | Destiny. [DS9] | |
| * | ulcartic virus. | 101.1J | Emperor's New Cloak, The. [DS9] |
| Ullians. | 018.045. | Violations. [TNG] | |
| Ullians. | 101.1K | Violations. [TNG] | |
| Ullians. (index, t) | 001.097.[G | Violations. [TNG] | |
| Ullians. (Alien retrieval systems) | 059.11G[A.a | Violations. [TNG] | |
| Ullians. (dress) | 018.045-a | Violations. [TNG] | |
| Ullians. (Grand project) | 018.045[A | Violations. [TNG] | |
| Ullians. (Other telepathic races) | 018.049[B.b | Violations. [TNG] | |
| Ultima Thule. | 003.3zKK.[E | Dramatis Personae. [DS9] | |
| Ultima Thule. | 101.1L | Dramatis Personae. [DS9] | |
| ultrasonic generator. | 101.1N | Heart of Stone. [DS9] | |
| ultrasonic generator. (covariant oscillator) | 083.14Y | Heart of Stone. [DS9] | |
| ultraviolet satellite. | 101.1O | Operation: Annihilate. [TOS] | |
| ultritium. | 101.1P | Manhunt. [TNG] | |
| Ulysses, U.S.S." | 101.1Q | Adversary, The. [DS9] | |
| Ulysses. | 069.066-a | Captain's Holiday. [TNG] | |
| * | Umali. (Under attack) | 018.176[A | Workforce, Part I. [VGR] |
| Umani sector. | 003.7F.[L | Muse, The. [DS9] | |
| Umani sector. | 101.1R | Muse, The. [DS9] | |
| Umbato, Lieutenant. | 025.34E.[L | Data's Day. [TNG] | |
| Umbato, Lieutenant. | 101.1S | Data's Day. [TNG] | |
| umbilical port. | 101.1T | Remember Me. [TNG] | |
| Umoth VIII. | 003.3zKK.[F | Maquis, The, Part II. [DS9] | |
| Umoth VIII. | 101.1U | Maquis, The, Part II. [DS9] | |
| * | Unai. | 029.43D.[O | Haunting of Deck Twelve, The. [VGR] |
| uncertainty principle. | 101.1V | Parallels. [TNG] | |
| Undalar. | 101.1W | Body Parts. [DS9] | |
| undari. | 101.1X | Tapestry. [TNG] | |
| * | under-space. | 101.1Z | Dragon's Teeth. [VGR] |
| Underhill, Pell. | 101.1AA | Clues. [TNG] | |
| undiscovered country, the. | 101.1AB | Star Trek VI: The Undiscovered Country. | |
| Unefra III. | 003.3zKK.[G | Improbable Cause. [DS9] | |
| Unefra III. | 101.2A | Improbable Cause. [DS9] | |
| Unferth. | 101.2B | Heroes and Demons. [VGR] | |
| * | Ungtae, Vedek. | 010.21A[H | What You Leave Behind. [DS9] |
| * | Ungtae, Vedek. | 101.2C | What You Leave Behind. [DS9] |
| Uniform Code of Justice. | 101.2D | Drumhead, The. [TNG] | |
| Uniform Code of Justice. (Starfleet legal procedures, 24th Century) | 019.11A.b | Drumhead, The. [TNG] | |
| uniforms, Starfleet. (2151) | 061APP2 | ||
| uniforms, Starfleet. (2250s-2370s, cadets) | 061.10. | ||
| uniforms, Starfleet. (2254) | 061.01. | ||
| uniforms, Starfleet. (2266) | 061.02. | ||
| uniforms, Starfleet. (2266) | 061.02C.a | ||
| uniforms, Starfleet. (2266) (index, 23rd-c) | 001.003.[Q | ||
| uniforms, Starfleet. (2266) (mirror universe) | 061APP1 | ||
| uniforms, Starfleet. (2271) | 061.03. | ||
| uniforms, Starfleet. (2271) | 061.03A | ||
| uniforms, Starfleet. (2274 to 2349) | 061.04. | ||
| uniforms, Starfleet. (2274 to 2349) | 061.04A | ||
| uniforms, Starfleet. (2350 to 2365) | 061.05. | ||
| uniforms, Starfleet. (2360s to 2370s, admirals') | 061.08. | ||
| uniforms, Starfleet. (2360s to 2370s, admirals') (index, 24th-c) | 001.004.[K | ||
| uniforms, Starfleet. (2360s to 2370s, captains') | 061.08A | ||
| uniforms, Starfleet. (2360s, alternate timeline) | 061.04B | ||
| uniforms, Starfleet. (2360s, mid) | 061.06. | ||
| uniforms, Starfleet. (2366) | 061.06A.e | ||
| uniforms, Starfleet. (2369) | 061.07. | ||
| uniforms, Starfleet. (2373) | 061.09. | ||
| uniforms, Starfleet. (2373) | 061.09B.b | ||
| uniforms, Starfleet. (2373, combat) | 061.09C | ||
| uniforms, Starfleet. (2375, dress) | 061.11. | ||
| uniforms, Starfleet. (2376, desert outfits) | 061.09A | ||
| uniforms, Starfleet. (2377, racing) | 061.14. | ||
| uniforms, Starfleet. (2395 on) | 061.13. | ||
| uniforms, Starfleet. (2800s) | 061.15. | ||
| * | Unimatrix Zero One. | 015.09. | Survival Instinct. [VGR] |
| * | Unimatrix Zero One. | 015.09-a | Survival Instinct. [VGR] |
| * | Unimatrix Zero. | 015.12. | Unimatrix Zero, Part I. [VGR] |
| * | Unimatrix Zero. | 015.12-a | Unimatrix Zero, Part I. [VGR] |
| * | Unimatrix Zero. (dreamscape) | 015.12-b | Unimatrix Zero, Part I. [VGR] |
| * | Unimatrix Zero. (A dreamworld) | 015.10[B | Unimatrix Zero, Part I. [VGR] |
| * | Unimatrix Zero. (freed from the collective) | 015.13.l | Unimatrix Zero, Part I. [VGR] |
| * | Unimatrix Zero. (Out of body experience) | 015.08A[A | Unimatrix Zero, Part I. [VGR] |
| United Earth Space Probe Agecy. | 007.14-b | Charlie X. [TOS] | |
| United Earth Space Probe Agency. | 101.2G | Charlie X. [TOS] | |
| United Federation of Planets. | 007.01. | Star Trek IV: The Voyage Home. | |
| United Federation of Planets. | 007.01-b. | Star Trek IV: The Voyage Home. | |
| United Federation of Planets. | 018.060-a | Attached. [TNG] | |
| United Federation of Planets. | 101.2H | Star Trek IV: The Voyage Home. | |
| United Federation of Planets. (index) | 001.007. | Star Trek IV: The Voyage Home. | |
| United Federation of Planets. (and genetic engineering) | 007.11. | ||
| United Federation of Planets. (and genetic engineering) (index, g e) | 001.075.[A | ||
| United Federation of Planets. (and other races) | 007.16. | ||
| United Federation of Planets. (and the Klingons) | 007.16A | ||
| United Federation of Planets. (applying for Membership) | 007.01B | ||
| United Federation of Planets. (at war) | 007.06. | ||
| United Federation of Planets. (Cardassian terrorists) | 013.04-a | ||
| United Federation of Planets. (cloning) | 0118.061-c | ||
| + | United Federation of Planets. (F) | 004.06-b | Star Trek V: The Final Frontier. |
| United Federation of Planets. (F) | 086.02H | Star Trek IV: The Voyage Home. | |
| United Federation of Planets. (fashion in the 21st Century) | 007.19B | ||
| United Federation of Planets. (fashion in the 23rd Century) | 007.19A | ||
| United Federation of Planets. (fashion in the 23rd Century) (index, 23rd-c) | 001.003.[D | ||
| United Federation of Planets. (fashion in the 24th Century) | 007.19. | ||
| United Federation of Planets. (fashion in the 24th Century) (index, 24th-c) | 001.004.[D | ||
| United Federation of Planets. (food and drink) | 007.12. | ||
| United Federation of Planets. (formation and history) | 007.01C | ||
| United Federation of Planets. (health in the 24th Century) | 007.01A | ||
| United Federation of Planets. (health in the 24th Century) (index, 24th-c) | 001.004.[N | ||
| United Federation of Planets. (justice) | 007.04. | ||
| United Federation of Planets. (leisure pursuits in the 24th Century) | 007.13. | ||
| United Federation of Planets. (Meeting chambers) | 007.01F[A | Star Trek VI: The Undiscovered Country. | |
| United Federation of Planets. (music) | 007.03F | ||
| United Federation of Planets. (penal systems) | 007.08. | ||
| United Federation of Planets. (penal systems) (index, c) | 001.068.[A | ||
| United Federation of Planets. (terrorist threats) | 007.07. | ||
| United Federation of Planets. (The Alpha quadrant) | 003.2[A.a | Star Trek IV: The Voyage Home. | |
| United Federation of Planets. (worlds) | 007.05. | ||
| units of measure. SEE: | 003.1A | ||
| universal translator. | 007.01Di-b | Metamorphosis. [TOS] | |
| universal translator. | 101.2I | Metamorphosis. [TOS] | |
| * | universal translator. | 206.008-a | Breaking the Ice. [ENT] |
| universal translator. (index, 23rd-c) | 001.003.[K | Metamorphosis. [TOS] | |
| universal translator. (beta radiation) | 082.06AI | Little Green Men. [DS9] | |
| + | universal translator. (ionic interference) | 089.05AD | Indiscretion. [DS9] |
| universal translator. (methods of communication) | 007.01Di.a | Metamorphosis. [TOS] | |
| universal translator. (nuclear fission) | 094.07L | Little Green Men. [DS9] | |
| universal translator. (Skrreean language) | 018.058-c | Sanctuary. [DS9] | |
| universal translator. (translation mix) | 100.19C | Sanctuary. [DS9] | |
| University of Betazed. | 101.2J | Tin Man. [TNG] | |
| Unnatural Selection. (unnamed disease) | 007.21D.[J | Unnatural Selection. [TNG] | |
| * | Unroth system. | 101.2L | Strange Bedfellows. [DS9] |
| upturned. | 101.2M | Nemesis. [VGR] | |
| Uri'lash. | 101.2O | Profit and Lace. [DS9] | |
| uridium. | 101.2N | Civil Defense. [DS9] | |
| uridium. (Cardassian Ore Processing Center. SEE: O P C) | 083.17U | Civil Defense. [DS9] | |
| uridium. (ore processing center) | 095.5G | Civil Defense. [DS9] | |
| Urodelean flu. | 007.21D.[B | Genesis. [TNG] | |
| Urodelean flu. | 101.2P | Genesis. [TNG] | |
| user code clearance. | 101.2Q | Hero Worship. [TNG] | |
| Ustard, Subcommander. | 101.2R | Broken Link. [DS9] | |
| Utopia Planitia Fleet Yards. | 032.09. | 11001001. [TNG] | |
| Utopia Planitia Fleet Yards. | 101.2S | 11001001. [TNG] | |
| * | Utopia Planitia Fleet Yards. | 206.006-a2 | Terra Nova. [ENT] |
| Utopia Planitia Fleet Yards. (A place of history) | 004.42[A | 11001001. [TNG] | |
| Utopia Planitia Fleet Yards. (Building Starfleet) | 007.05H[B | 11001001. [TNG] | |
| uttaberries. | 018.003-a | Menage a Troi. [TNG] | |
| uttaberries. | 101.2T | Menage a Troi. [TNG] | |
| uttaberry crepes. | 018.003-b | Armageddon Game. [DS9] | |
| uttaberry crepes. | 101.2U | Armageddon Game. [DS9] | |
| Ux-Mal. | 004.48-a | Power Play. [TNG] | |
| Ux-Mal. | 101.2V | Power Play. [TNG] | |
| Ux-Mal. (index, nc b) (incarcerated spirits) | 001.072.[N | Power Play. [TNG] | |
| Ux-Mal. (Evil presence) | 058.067[A.d | Power Play. [TNG] | |
| Ux-Mal. (Strange life) | 004.48[B | Power Play. [TNG] | |
| Uxbridge, Kevin. | 057.11. | Survivors, The. [TNG] | |
| Uxbridge, Kevin. | 069.050-a | Survivors, The. [TNG] | |
| Uxbridge, Kevin. | 101.2W | Survivors, The. [TNG] | |
| Uxbridge, Rishon. | 057.11A | Survivors, The. [TNG] | |
| Uxbridge, Rishon. | 101.2X | Survivors, The. [TNG] |