Ideas do not respect national frontiers, and this is especially so where language and other traditions are in common.

We crossed the frontier yesterday.

Many families left to make a new life on the frontier.

Then Dido thus, with downcast look sedate: / "Take courage, Trojans, and dismiss your fear. / My kingdom's newness and the stress of Fate / force me to guard far off the frontiers of my state."

Bernard Kouchner, who established Medecins Sans Frontieres, did not oppose the Iraq war.

Many families went west to make a new life on the frontier.

Where the frontier of science once was is now the centre.

Many causes produce war. There are ancient hatreds, turbulent frontiers, the "legacy of old forgotten, far-off things, and battles long ago." There are new-born fanaticisms. Convictions on the part of certain peoples that they have become the unique depositories of ultimate truth and right.

The soldiers headed for the frontier with caution.

The JAXA-sponsored education-focused experiment known as THE SPACE FRONTIER STUDIO - KIBO enables new livestreaming capabilities on the station.