Radio, Penal and 10-Codes:

211: Armed Robbery
242: Assault & Battery
245: Assault with a deadly weapon
2735 or 273.5: Domestic Violence
311: Indecent exposure (code also used for drunks urinating behind the bars in HB)
415: Disturbance (415 loud party, 415 subject on a bus, 415 construction, etc.)
459: Burglary
459 audible: Burglar alarm going off
5149 (or 5149.5): [Unofficial] term used by law enforcement for someone who isn't quite 5150 (half-crazy).
5150: Crazy person
911B: Meet with Officer
925A: Suspicious person
927: Unknown trouble
927C: Check the area (for the suspect)
10-1: Your radio sounds like crap
10-2: Your radio sounds good
10-4: OK-Acknowledged
10-6: Busy (i.e.: Can you respond to the call? No, I'm 10-6).
10-9: Repeat what you just said
10-17: Enroute (to the call)
10-20: What's your location
10-21: Contact by phone
10-22: Disregard/Cancel
10-27: Drivers license check
10-28: Registration check (Is this vehicles registration current and active?)
10-29: Veh stolen check (is this vehicle stolen?)
10-33: Hold the channel for emergency traffic
10-35F (Frank): Felony warrant
10-35M (Mary): Misdameanor warrant
10-35P (Paul): Probation
Code 3: Lights and Siren (also referred to as "Rolling Code")
Code 4: All clear, everything is under control
Code 6: Officer is busy on a call
Code 20: Officer welfare check

Abbreviations and acronyms:

ADW: Assault with a Deadly Weapon

AIQ: Available in Quarters (typically an FD term meaning the fire apparatus is back inside the station)

ALPR (or "ALPR's hit"): Automatic/Automated License Plate Reader/Recognition (strategically placed pole-mounted [typically] cameras throughout a city scanning license plates looking for stolen vehicles).

ALS: Advanced Life Support (term commonly used by paramedics)

AMR: (American Medical Response) Ambulance Service
Audible: A burglar/fire alarm that can be heard
Baywatch: It's the Lifeguard division of the Los Angeles County Fire Department
BEARCAT: "Ballistic Engineered Armored Response Counter Attack Truck." SWAT's armored vehicle.
"Beer Run": Theft of beer/alcohol (usually from a convenience store)
BLS: Basic Life Support (less severe than an ALS request)
BOLO: Be On the Look Out
“The Boulevard”: Hawthorne Boulevard [usually]
"Bud": Budlong Avenue
"Cal Personal": California Personalized (Vanity) License Plate
CARE: Ambulance Service
CDL: Can be either a Commercial Driver's License or a California
Driver's License
CHP (or "Chippie"): California Highway Patrol
"Cut Your Code": Stop responding with lights and siren (i.e.: ...
Sufficient units on scene, cut your code).
DB: Dead body
DBR: Dead Body Recovery
DOB: Date of Birth
DCFS: Department of Children and Family Services
DL: Driver's License
DOT: Direction of Travel
DP: Disturbing Party (The person who is causing the problem)
DR or DR Number: Departmental Report
ETOH: Paramedic (usually) term for an alcohol related issue/drunk 
(i.e.: ...The patient's chief complaint is ETOH)
"E-TRIG" or "E-Trigger": An officer's panic (emergency)
button on their handheld radio
Gerber: Ambulance Service
​Ghetto Bird: Slang term used for police helicopter
GMH: Gardena Memorial Hospital
GOA: Gone On Arrival
GSR Kit: Gunshot Residue Kit...used by forensics in evidence collection.
GSV: Gunshot victim
Harbor: Harbor-UCLA Medical Center (i.e.: ...Transporting patient 
to Harbor)
HBD: Has been drinking
“The Highway” or PCH: Pacific Coast Highway
"The Jetty:" The rock pile deflecting the suf just west of Esplanade/Topaz St in Redondo Beach
JO: Just occurred (i.e.: ...units respond to a 459 JO)
K9: Police dog
LACOFD: Los Angeles County Fire Department
LACOSO or LASD: Los Angeles County Sheriff
LAFD: Los Angeles (City) Fire Department
LAPD: Los Angeles Police Department
LASD: Los Angeles Sheriff Department
LCM: Little Company of Mary Hospital
"Man Ave" Another way to say Manhattan Avenue...not to be 
confused with Manhattan Beach Blvd.
MBB: Manhattan Beach Boulevard
MDT: Mobile Data Terminal...the computer in a police car.
McCormick: Ambulance Service
MedAlert: Term used by police to contact hospitals in the area to be on the lookout for shooting victims. (i.e.: ...everyone fled the scene after the shots were better send a MedAlert).
NCIC: National Crime Information Center
NFD: No Further Description
NFI: No Further Information
Non-desirous: Victim does not want to press charges (i.e.: ...the clerk just wants the stolen merchandise back)
OIS: Officer involved shooting
"On the patch"is an LASD crime broadcast for something 
significant that usually just occurred
"Ped": Pedestrian (i.e.: ...the accident was vehicle vs. ped)
PV: Palos Verdes
RBB: Redondo Beach Boulevard
Redondo Beach Ave: N/S road between Marine Ave and MBB...
Not to be confused with Redondo Ave or Redondo Beach Blvd
Res: Residence
RIC: Rapid Intervention Crew (is a fire dept. term)
RO: Registered owner (of the vehicle)
RPV: Rancho Palos Verdes
SBRPCA or “South Bay”: South Bay Regional Public 
Communications Authority (Dispatch)
SCC: Sheriff's Communications Center (LASD Dispatch)
SEB: LASD term used for the Special Enforcement Bureau (Special Weapons Teams).
Shelter-in-Place: This is a precaution aimed to keep you safe while remaining indoors (i.e.: shooter roaming the streets, send an alert to residents in the area to shelter-in-place)
"Slow roll"Back-up request, non-emergency request
SO: Sheriff's Office

Strong Arm: A form of armed robbery by the user of bodily force

TFD: Torrance Fire Department

“The Strand”: Essentially, it's the North/South bike/walk path that 
runs from 45th St to about Herondo St
TMH: Torrance Memorial Hospital
UTL: Unable to locate (the suspect, the victim, the vehicle, etc.)
Vic: Abbreviated way to say "Victim"
Waterline: Where surf meets sand (i.e.: Units patrolling the waterline 
looking for passed out drunks on the beach)
WC: Watch Commander
Wit: An abbreviated way to say "Witness"