first response unit

first fire mixture / first-fire mixture

first response

audio-response unit

credible first strike capability

first aid facility

first aid kit

first echelon maintenance

first echelon medical equipment maintenance

first hand information

first impression report (FIR) (post exercise)

first lieutenant = (брит.) lieutenant

first light

first responder (emergencies)

First Sergeant (1SGT)

first watch

first-aid skills

first-line reserve

individual first-aid kit (IFAK)

first lights

Petty Officer First Class (PO1)

Private First Class (PFC)

Sergeant First Class (SFC)

tactical first aid kit

first round fire for effect

medical kit / med kit / medi kit / first aid kit

medical pouch, med pouch, medi pouch, first aid pouch, medical pack

first iteration of fuel (the)

first gear

first stage fuel filter

first-hand observations

first-line transport

drone war (world’s first drone war)