AK-47 - A Russian-designed assault rifle, used by the Somalis throughout the fight.

APC - Armored personnel carrier, a tanklike vehicle that carries troops.

BDUs - Battle Dress Uniforms, in this case, desert tan camouflage fatigues.

Blackhawk - A Sikorsky-made UH-60 helicopter used primarily as a troop transport. It has a pilot and co-pilot and two crew chiefs who each man miniguns, extremely rapid-fire machine guns that fire up to 4,000 rounds per minute.

CAR-15 - Colt Automatic Rifle 15, an automatic weapon more compact and lightweight than an M-16 that fires a high velocity 5.56mm round.

Chalk - A squad of soldiers, usually about a dozen, assigned to a helicopter. Chalk One roped down at the southeast corner of the target block, Chalk Two at the northeast corner, Chalk Three at the southwest corner, and Chalk Four near the northwest corner.

• Chalk One - Led by Ranger commander Capt. Mike Steele and Lt. Larry Perino. It was at the southeast corner of the target house.
• Chalk Two - Led by Lt. Tom DiTomasso. It was at the northeast corner of the target house.
• Chalk Three - Led by Sgt. First Class Sean Watson. It was at the southwest corner of the target house.
• Chalk Four - Led by Staff Sgt. Matt Eversmann, it was supposed to have been at the northwest corner of the target house, but was out of position one block north.
  The Rangers' positions near the target

Command Copter - Also called the "C-2 Bird" (for command and control), this is a Blackhawk circling high above the city with air commander Lt. Col. Tom Matthews and ground force commander Lt. Col. Gary Harrell helping to direct the action.

Command Net - The radio frequency linking the various unit commanders and primary communications network for the mission. There were other, separate frequencies assigned to the Rangers (Company Net), Delta (Assault Net) and the helicopters (Air Net).
Selected radio transmission and transcripts

Delta Force - The US Army's elite counter-terrorism unit, made up of three 150-man squadrons of specially trained professional soldiers, most of them in their late 20s or early 30s, products of a tortuously rigid selection process. The Army does not officially acknowledge that the unit exists. The Rangers called them ''the D-boys.''

Fast rope - The technique used by assault troops who slide down thick nylon ropes from helicopter, or the rope used in this manuever.

Flash-bang - A harmless grenade that gives off smoke and makes noise.

.50-gunner - The man behind a .50-cal. machine gun, usually mounted on a humvee. On round can rip a grapefruit-sized hole in a cinderblock wall.

.50-cal. - A Browning .50-cal. machine gun, mounted usually on a humvee, which can continuously fire a belt of ammunition. A .50-cal. round can poke a grapefruit-sized hole in a cinderblock wall.

Five-ton - A five-ton capacity truck with a flat bed in back used as a transport.

Habr Gidr - A powerful Somalia subclan, part of the Hawaye, one of the five principle clans in that desert nation. During Task Force Ranger, this clan was led by Mohamed Farrah Aidid.

Hawlwadig Road - The wide, paved north/south road that ran in front of the target house and Olympic Hotel.
Map of the Mogadishu target area

Hoo-ah - The grunted greeting exchanged by Rangers, it is also a slang term for a Ranger.

Humvees - The wide-bodied Army vehicles that replaced the jeep as the all-purpose military ground transport. There are cargo humvees with sloping hatch-backs, and attack humvees with a gun turret on top, outfitted with either a .50-cal. machine gun or a Mark-19 automatic grenade launcher. Humvee comes from HMMWV, the military acronym for high-mobility multipurpose wheeled vehicle.

JOC - The Joint Operations Center, a dilapidated building at Task Force Ranger's beachfront base where commanders of the various units, Army, Navy and Air Force monitored the fight on TV screens and radio.

K-4 traffic circle - One of the major traffic roundabouts in southern Mogadishu.

Kevlar - Protective material capable of stopping small caliber bullets and shrapnel. Kevlar panels lined the floors of the Blackhawks, and Rangers wore newly-issued Kevlar vests with a ceramic front plate capable of stopping larger caliber rifle rounds. Military-issue helmets are also lined with Kevlar.

Khat - A bitter green plant used by Somalis that acts as a stimulant when chewed.

LAW - A light antitank weapon. The disposable plastic launcher weighs only three pounds.

Little Birds - The fast, tiny and highly-manueverable bubble-front AH-6 (Attack Helicopter-6) and MH-6 (Military Helicopter-6) helicopters. The AHs are attack helicopters, armed with miniguns and rockets. The MHs deliver Delta soldiers to their target, carrying them on benches mounted on the outside.

Lost Convoy - The original ground convoy of nine humvees and three five-ton trucks commanded by Lt. Col. Danny McKnight. The convoy's mission was to drive Somali prisoners and the assault force back to base. They were whittled down to six humvees and two trucks. Carrying 24 prisoners, they got lost trying to find their way to the two Blackhawk crash sites.

M-16 - The standard-issue automatic rifle carried by American soldiers.

M-60 - A relatively lightweight, hand-carried machine gun with a bipod that can fire a continuous belt of 7.62mm rounds. The M-60 is a ''crew served,'' one that is handled by a gunner and an assistant. The Rangers call the M-60 a ''pig'' because of the low, grunting sound it makes when fired.

M203 - A grenade-launching tube sometimes mounted under the rifle barrel of an M-16.

Mark 19 - An automatic grenade launcher, usually mounted on a humvee, which rapidly fires armor-piercing 40mm rounds.

Minigun - A electric-powered machine gun mounted on helicopters capable of firing up to 4,000 rounds of 7.62mm ammunition per minute.

MP-5K - A German submachine gun that fires 9mm rounds. The pilots called them "skinny-poppers."

Nightstalkers - The Special Operations Aviation Regiment (SOAR) 160th US Army Division based at Ft. Campbell, Ky., considered the Army's finest helicopter aviation unit, specializing in night flying and combat.

NODs - Night vision devices that look like mini-binoculars. They amplify extremely small amounts of light to enable soldiers to see in the dark.

OH-58 - Survelliance helicopters equipped with sophisticated listening devices and cameras, capable of transmitting live video images of the battle and instant still images.

P-3 Orion - A propeller-driven spy plane that flew high over Mogadishu for 10 hours on the day of the battle. It is outfitted with extraordinarily high-powered surveillance cameras and electronic-jamming devices. An Orion orbited high over Mogadishu, out of range of Somalian weaponry, for the entire battle.

RLTW - Acronym used by Rangers, meaning "Rangers lead the way."

Romeo 64 - The radio call sign for the Command helicopter, a Blackhawk circling high overhead. Lt. Col. Gary Harrell is the voice communicating with troops on the ground. His call sign is abbreviated as R64 in the radio transcripts.

RPG - Rocket propelled grenade. It is fired from a tube like a small missile.
How Somalis downed U.S. helicopters with RPGs

SAW - Squad automatic weapon, a hand-carried machine gun with a bipod on the gas cylinder.

SEAL - The Navy's elite commando unit. SEAL stands for sea, air & land. Team Six was assigned to Task Force Ranger in Somalia.

Star 41 - The radio code name for the Little Bird piloted by Chief Warrant Officer Keith Jones.

60-gunner - Operator of an M-60 machine gun.

Super - The radio code name for the Blackhawks in the battle. The helicopters were called Super 61, Super 62, Super 64, Super 68, etc.

• Super 61 - The radio code name for the Blackhawk helicopter piloted by Chief Warrant Officer Cliff Wolcott.
• Super 64 - The radio code name for the Blackhawk helicopter piloted by Chief Warrant Officer Mike Durant.
• Super 62 - The Blackhawk piloted by CWO Mike Goffena.

Target Building - The three-story house on Hawlwadig Road one block north of the Olympic Hotel where a group of Aidid clansmen were meeting the afternoon of Oct. 3, 1993. It was stormed by Delta commandos and 24 Somalis were taken prisoner.

Task Force Ranger - The 450-man force deployed to Mogadishu in late August 1993, commanded by Maj. Gen. William F. Garrison and made up primarily of Delta Force Squadron C from Fort Bragg, N.C., Bravo Company of the 75th Ranger Regiment from Fort Benning, Ga., and the helicopter unit called ''Nightstalkers,'' the 160th Special Operations Aviation Regiment from Fort Campbell, Ky.

TOW A heavy antitank weapon. Its name is derived from its description as a tube-launched, optically tracked, wire command-link guided missile.