What does CC refer to when describing an engine?

I have been learning about various older cars on Wikipedia. I've always wondered what the "cc" refers to in the engine description. For example:

• 1964–1969 Porsche 911: 1991 cc
• 1965-1969 Porsche 912: 1582 cc

1 cc = 1 cubic centimeter (volume of displacement)

1000 cc = 1 L, so a 2 Liter car is about 2,000 cc (the liters may be rounded when reported)

Some American cars are listed in ci or cid (cubic inches of displacement). 1L = 61.02 cid, so the Ford '5.0L engine' is their 302 cid engine.

Since cars engines typically total well over a liter, they aren't often marketed in ccs. Motorcycle and smaller motors aren't, however, so cc figures like 500cc, 600cc or 900cc are more common.

See this wikipedia article on Engine Displacement units of measure for more details.

Cubic centimetre

It's the amount of displacement of the engine

One complete cycle of a four-cylinder, four-stroke engine. The volume displaced is marked in orange.

• Do you mean "displacement"? So if I understand correctly, it's the same thing as when they say a "2.0 Liter engine" only in this case for the Porsche 911 it's 1.991 Liter engine? Dec 29 '13 at 7:23
• Exactly. You will find it used with smaller displacement engines (something less than a liter displacement) or older engine descriptions. With newer engine descriptions they tend to just round the numbers, so "1991cc" becomes "2l" or "2.0l". Dec 29 '13 at 11:58
• @Andrew Yes Displacement lol. It was late when I wrote that. :) Dec 29 '13 at 17:47
• This may be out of topic but if I understand correctly the figure, by altering the route of the cylinders you can change (increase or decrease) the volume displaced. Is this correct? Dec 31 '13 at 11:41
• @Vaggelis_Z No, displacement is simply the volume of air pumped through the engine in one complete cycle. Dec 31 '13 at 17:52