weird initials

An ECP is an Engineering Change Proposal. It's also all of these:

Enhanced Capability Port
Electromagnetic Compatibility Program
Electronic Communications in Probability
École Centrale Paris
Extended Capabilities Port
Encryption Control Protocol
Escadrilles Canadiennes de Plaisance
eosinophil cationic protein
Election Commission of Pakistan
Emergency Conservation Program
East Coast Parkway
Emergency Contraceptive Pill
Empty Category Principle
External Counterpulsation
Electronic Check Presentment
East Coast Park
Estradiol Cypionate
Emergency Care Practitioner
Employee Concerns Program
Eye Care Practitioner
Enlisted Commissioning Program
Effective Core Potential
Electrochemical Plating
Early Commissioning Program
Electron Capture
Eye Care Provider
European Cancer Prevention Organization
Enhanced Call Processing
European Common Proposal
Environmental Condition of Property
Electrochemical Corrosion Potential
External Casing Packer
Essential Community Provider
Experimental and Clinical Psychopharmacology
Extended Cutting Plane
Export Control Program
Electron Channeling Pattern
Executive Cellular Processor
Essence Communications Partners
Endoscopic Cyclo Photocoagulation
Empresa Colombiana de Petróleos
Earth Contact Products
Estimated Critical Position
Error Correction Protocol
Episcopal Church At Princeton
Electricity Capacity Planning
Elderly Cancer Patients
Entrepreneurial Competitive Profile
Employee Contribution Project
Emergency Call Processing
Enhanced Communication Protocol
Emission Control Program
Equivalent Circuit Parameter
Executive Control Program
Exposed Conductive Part
Emergency Contraception/Contraceptive Pill
Effective Communities Project
Eosinophil Chemotactic Protein
Electronic Check Presentation
Exercise Control Plan
Engineers' Club of Philadelphia
Exchange Coupled Pair
Extended Care Physicians
Events Center Paddock
Equipment Change Proposal
Emergency Command Precedence/Procedure
Environmental Control Processor
Equipment Collection Point
Excessive Cross-Post(ing)
East Capitol Pensionne
Exception Report Collection Process
Emergency Change Proposal
Emergency Cleanup Powder
Empowerment Contracting Program
Environment Compliance Plan
Electric Cooling Pump
Extended Care Paramedic
Expected Coverage Plan
Electronic Product Codec
Environmental Control Panel
Energy Conservation Product
Excepted Coverage Plan
Equivalent Component Pair
External Compliance Plan
Electronic Change Permit
Eject Chamber Pressure
Electronic Combat Pilot
European Chiefs of Police
EVGA Control Panel
Electronically Controlled Pneumatic
E-Commerce Platform
Early Commencement Program
Extended Care Program
Echo Chamber Project
Erosion Control Products
Environmental Conservation Program
Eye Care Professional
Entry Control Point
Early College Program
European Commercial Paper
Escherichia Coli Common Pilus

But my most favorite definition for ECP is Easton Colt Pierce who was born into our little family at 03:06 June 5, 2012 weighing 7 lbs 15 oz and measuring 21" with a 14" circumference head.

If the circumference of your head was 66.7% your height, people would laugh at you.