Meaning of 1.2L, 1.4L, 1.6L,engine in a car?

In a car, which has a multi(4/6/8) cylinder engine, the above nomenclature viz. 1.6L,1.4L, etc. refers to the combined volume capacity of all the cylinders( expressed in cubic centimeters, 1L=1000 cc).  Here volume capacity refers to the swept volume or displacement volume or breathing capacity of the cylinder. It is basically the volume of air that can be sucked insde the cylinder as the stroke moves from TDC to BDC.
Swept Volume,  V= pi/4*d^2*L*K   , where
                                           d- Bore, L-Stroke,  K-no. of cylinders.


This is the common terminology used to specify the engine size. A 1.2L engine means a 1.2 litre engine, which is equal to 1200cc (cc = cubic capacity).  Hope that explains it!

Pros/Cons:
Usually, higher swept volume means higher power and subsequently higher fuel consumption. This is because
Power, P= Mean Cyl.Pressure*Stroke*Piston area*No. of power strokes*No. of cylinders.
 So, Power generated is a directly proportional to the cylinder capacity.
However, now with different fuel efficiency techniques it needn't be that the higher capacity engine consumes more fuel than the lower capacity one.

Its a term that sometimes appears confusing. Some take it to be the total engine cylinder.  Actually, its the swept volume.
Total Engine Cylinder Volume is equal to the product of Volume of a single cylinder with the number of cylinders in the engine assembly. Number of cylinders depends on the manufacturer and also as per the requirement and needs.
Total Cylinder Volume=Swept Volume+Clearance Volume

Now when we say 1.2L engine. It refers to the total swept volume of the engine (combining all cylinders). The volume that can be sucked in a suction stroke(when piston moves from TDC to BDC)  is this swept volume. It gives you the breathing capacity of the engine.