Wikipedia
European bonds are suggested government bonds issued in Euros jointly by the 19 eurozone nations. Eurobonds are debt investments whereby an investor loans a certain amount of money, for a certain amount of time, with a certain interest rate, to the eurozone bloc altogether, which then forwards the money to individual governments.
Eurobonds have been suggested as a way to tackle the European sovereign debt crisis as the indebted states could borrow new funds at better conditions as they are supported by the rating of the non-crisis states.
Because Eurobonds would allow already highly indebted states access to cheaper credit thanks to the strength of other Eurozone economies, they are controversial, and may suffer from the free rider problem.