U

U bolt

U-joint (universal joint / universal coupling)

U-leather ring

U of the backsight

U.S. Aids to Navigation System

U.S. Naval Institute

U-shaped cartridge guide

U-shaped vessels

U slot of piston

U-turn

U-turn / 180º turn

U – UNIFORM

U washer

уard bird

уard master / yard-master

UAS Control Segment (UCS)

UAV company

UAV imagery

UBACS / Under Body Armour Combat Shirt

UGL bandolier

UGL pouch (UGL / Underslung Grenade Launcher)

UHF-band (ultrahigh frequency)

UHF communications equipment

UHF radio receiver transmitter (RRT)

uhlan (lance; lancer; lances; ulan)

уield a fortress

уield ground

уield oneself prisoner

уield success

Ukraine Defence Contact Group (UCG)

Ukraine Defense Contact Group (UDCG) / Ramstein group

Ukraine Security Assistance Initiative (USAI)

Ukrainian Armed Forces

Ukrainian Cyber Alliance

Ukrainian hacktivist groups

UKUSA (The United Kingdom – United States of America Agreement)

ulterior action

ultimate destination (final destination)

ultimate disposal

ultimate motor fuel

ultimate strain

ultimate user

ultimate weapon

ultimatum

ultra-high frequency

ultra-high striking velocity

ultra-high velocity cartridge

ultra-range gun

ultra-silent cruise-missile-carrying nuclear submarine

ultrahigh frequency (UHF)

ultrahigh striking velocity

ultrahigh velocity cartridge

ultralight ceramic composite armor

ultrashort journey

ultrasonic absorption

ultrasonic communication

ultrasonic corrosion detector

ultrasonic inspection

ultrasonic machining

ultrasonic sensor

ultrasonic test

ultrasound

ultraviolet absorption

ultraviolet light

ultraviolet radiation

ultraviolet (UV)

umbilical (cable, hose)

umbilical cord

umbrella agreement

umbrella approach

umbrella barrage

umbrella fighter

umpire

umpire control organization

umpiring

UMPK

UN Commission on Sustainable Development

UN Framework Convention on Climate Change (UNFCCC)

UN-led International Police Task Force

UN-mandated force

unable to extinguish the fire

unacceptable damage

unarmed

unarmed combat

unarmored wheeled vehicle

unassigned

unassisted control

unattached

unattended access

unauthorized absence

unauthorized absence (UA)

unauthorized activities

unauthorized disclosure of classified information

unauthorized operation

unavoidable collision

unbaffled cylinder

unbalance

unbalanced gasoline

unbiased approach

unblock the road

unblocking

unbreakable glass

unbroken flow of supplies

unbroken peace

unburied mine

unburned hydrocarbons

unbuttoned

unbuttoned driving

uncap

uncap a shell

uncase

uncertain environment

uncertainty

unclassified (security classification)

uncock

unconcealed position

unconditional discharge

unconditional surrender

unconsolidated

uncontaminated area

uncontrollable side-skid

uncontrolled airspace

uncontrolled automatic fire

uncontrolled crossing point

uncontrolled flight

uncontrolled mosaic

uncontrolled route

uncontrolled side-skid

unconventional warfare (UW)

unconventional weapons

uncork an advance

uncorroborated

uncouple

uncoupling position

uncowled

uncrewed

uncrewed aerial combat vehicle (UACV)

uncrewed aerial kamikaze drone

uncrewed aerial vehicle

Uncrewed Air(craft) / Aerial System (UAS)

uncrewed aircraft system

uncrewed boat

uncrewed ground kamikaze drone

uncrewed ground vehicle ((UGV)

uncrewed spacecraft

uncrewed surface craft

uncrewed surface vehicle

uncrewed surface vessel (USV)

uncrewed surface vessel

uncrewed undersea vehicle

uncrewed underwater vessel

uncushioned motion

undeclared member of the intelligence or counter-intelligence agencies

under a deadly fire

under armor auxiliary power unit (UAAPU)

under arms

under barrel grenade launcher (UBGL)

under canvas

under command

under command aircraft

under command of

under cover of

under cover of civilian research

under cover of the Consulate General

under cultivation

under deep cover

under duress

under fire

under-folding stock

under hatches

under hood

under-lever

under nonnuclear conditions

under nuclear conditions

under one's own steam

under orders (of)

Under Secretary of Defense for Acquisition, Technology, and Logistics (USD AT&L)

Under Secretary of Defense for Intelligence USD(I)

Under Secretary of Defense (USD)

under smoke

under-strength unit

under suspicion of posing a threat to democracy

under the forest canopy

under-vehicle improvised explosive device (UVIED)

under way

under way aircraft

under-wing probe-and-drogue tanking pod

under zero angle of incidence

underbelly spine

undercapacity

undercarriage

undercarriage activation

undercarriage bay

undercarriage door

undercover agent

undercover apparatus

undercover intelligence asset

undercover international apparatus

undercover movement

undercover operation