Milan Malpensa Airport, in Milan, Italy.

What is the difference between MXP and LIMC?

MXP is the IATA code, used commercially — tickets, timetables, luggage tags. LIMC is the ICAO code, used operationally by pilots and air traffic control, and assigned geographically by region.

Is MXP the same as LIN?

No. LIN is linate, seven miles from central Milan and much more convenient. MIL covers both.

What airport is MXP?

MXP is

Milan Malpensa Airport

Milan, Italy

Why the code is MXP

Milan malXPensa — from Malpensa, the heath it was built on, whose name means roughly "ill-thought-of".

This is the explanation in general circulation and it is very likely right, but no primary document has been published that settles it. Treated as an account rather than a fact.

The airport

IATA code: MXP
ICAO code: LIMC
Airport: Milan Malpensa Airport
City: Milan, Italy
Code origin: The usual account, unverified

Malpensa is 30 miles from Milan, and the city's closer airport, Linate, holds LIN. The name Malpensa long predates the airport and refers to the poor farmland of the heath.

Codes people book by mistake

Code	What it actually is
LIN	Linate, seven miles from central Milan and much more convenient. MIL covers both.

The other code, LIMC

Every airport has two codes. The three-letter IATA code, MXP, is the one on your boarding pass and your luggage tag, and it is assigned for commercial use. The four-letter ICAO code, LIMC, is the one pilots and controllers use, and it is assigned geographically: the first letter or two identify the region, so every airport in the same part of the world shares a prefix. That is why LIMC looks nothing like MXP.

Common questions

What airport is MXP?: Milan Malpensa Airport, in Milan, Italy.
Why is Milan's airport called MXP?: Milan malXPensa — from Malpensa, the heath it was built on, whose name means roughly "ill-thought-of".
What is the difference between MXP and LIMC?: MXP is the IATA code, used commercially — tickets, timetables, luggage tags. LIMC is the ICAO code, used operationally by pilots and air traffic control, and assigned geographically by region.
Is MXP the same as LIN?: No. LIN is linate, seven miles from central Milan and much more convenient. MIL covers both.

Italy Capital, area, population and currency
The flag of Italy Colours, symbols and lookalikes
Airport codes in Italy 2 here
What airport is FCO? Leonardo da Vinci-Fiumicino Airport, Rome

Sources

OurAirports — OurAirports (Public domain)

How these figures are compiled and checked