While Thursday’s communiqué merely omitted a single sentence, and Mr. Draghi sought to downplay the importance of the change, investors appeared to find it significant.

Markets reacted swiftly, with the euro jumping as much as 0.5 percent against the dollar, and the yield on the German 10-year bond, the benchmark for the region, rising five basis points.

“It’s a tacit acknowledgment that the economic outlook in Europe is rosier than it was,” James Athey, a senior investment manager at Aberdeen Standard Investments, said in a statement. He added, “The reaction should not be overdone. This is an infinitesimal step forwards.”

Some analysts had predicted that the central bank would make no changes in the language it uses to communicate its intentions to financial markets, in light of a confused election result in Italy.

On Sunday about half of Italians voted for populist candidates on the left and right, and left no party with a clear mandate to form a government. There is now very little chance that the country will make the sweeping changes needed to break its economy out of prolonged stagnation.

Its political deadlock and economic doldrums are a threat to the rest of the common currency area. Italy’s government debt, measured as a percentage of economic output, is among the highest in the world and, in Europe, second only to Greece’s.

But Italy also has the eurozone’s third-largest economy, with output 10 times that of Greece, making it a far bigger danger to the region’s financial stability if investors begin to doubt the government’s solvency.