| unico | only |
| Unico Anello | One Ring |
| Unico indizio la luna piena | Cycle of the Werewolf |
| Unico Wilhelm graaf van Wassenaer | Unico Wilhelm van Wassenaer |
| Unico Wilhelm Graf van Wassenaer | Unico Wilhelm van Wassenaer |
| Unicode | Unicode |
| unicolore | all one colour |
| Unicorn | Unicorn |
| unicorno | unicorn |
| Unicredito Italiano | UniCredit |
| unicum | folly |
| Unidad Popular | Unidad Popular |
| Uniejów | Uniejów |
| Unieux | Unieux |
| unifacciale | unifacial |
| unificabile | unifiable |
| unificare | unite |
| unificarsi | unite |
| unificato | united |
| unificazione | unification |
| Unified Modeling Language | Unified Modeling Language |
| UNIFIL | United Nations Interim Force in Lebanon |
| unifloro | uniflorous |
| Uniform Resource Locator | Uniform Resource Locator |
| uniformare | adapt |
| uniformarsi a | conform to |
| uniforme | equable |
| uniforme da campo | battle dress |
| uniformemente | uniformly |
| Uniformitarismo | Uniformitarianism |
| uniformità | uniformity |
| Unifredo I di Tolosa | Humfrid |
| unigenito | native |
| UNIIMOG | United Nations Iran-Iraq Military Observer Group |
| UNIKOM | United Nations Iraq-Kuwait Observation Mission |
| unilaterale | unilateral |
| unilateralismo | unilateralism |
| Unilever | Unilever |
| Unimog | Unimog |
| Union | Union |
| Union City | Union City |
| Union Europea de Futsal | European Union of Futsal |
| Union für Südtirol | Union for South Tyrol |
| Union Internationale des Chemins de Fer | International Union of Railways |
| Union Luxembourg | Union Luxembourg |
| Union Pacific | Union Pacific |
| Union Sportive Arlequins Perpignan | USA Perpignan |
| Union sportive Colomiers rugby | US Colomiers |
| Union sportive dacquoise | US Dax |
| Union sportive montalbanaise | US Montauban |
| Union Valdôtaine | Valdotanian Union |
| unione | alliance |
| Unione Africana | African Union |
| Unione Astronomica Internazionale | International Astronomical Union |
| Unione Calcistica Belga | Royal Belgian Football Association |
| Unione calcistica dei Caraibi | Caribbean Football Union |
| Unione Ciclistica Internazionale | Union Cycliste Internationale |
| Unione civile in Italia | Recognition of gay unions in Italy |
| Unione coniugale | Marriage |
| Unione Cristiana | ChristianUnion |
| Unione Cristiano Democratica | Christian Democratic Union |
| Unione Cristiano-Sociale in Baviera | Christian Social Union of Bavaria |
| Unione degli Atei e degli Agnostici Razionalisti | Italian Union of Rationalist Atheists and Agnostics |
| Unione dei Democratici Cristiani e di Centro | Union of Christian and Centre Democrats |
| Unione dei Democratici per la Repubblica | Union of Democrats for the Republic |
| Unione del Maghreb Arabo | Arab Maghreb Union |
| Unione delle Corti islamiche | Islamic Courts Union |
| Unione delle Gioventù Comuniste di Spagna | Communist Youth Union of Spain |
| Unione delle Repubbliche Socialiste Sovietiche | USSR |
