What is the meaning of Ensign?

A badge of office, rank, or power.

The lowest grade of commissioned officer in the United States Navy, junior to a lieutenant junior grade.

A flag or banner carried by military units; a standard or color/colour.

The principal flag or banner flown by a ship (usually at the stern) to indicate nationality.

Any prominent flag or banner.

A junior commissioned officer in the 18th and 19th centuries whose duty was to carry the unit's ensign.

To designate as by an ensign.

To distinguish by a mark or ornament.

To distinguish by an ornament, especially by a crown.

Source: wiktionary.org