The vocabulary that flag designers reach for — adapted from Wikipedia's Glossary of vexillology. Use it as a quick reference while you design.
The background of a flag; the colour behind the charges.
The half or edge of a flag nearest the flagpole; also the vertical dimension.
The half or edge of a flag furthest from the flagpole; also the horizontal length.
A quarter of a flag — most often the upper-hoist quarter (e.g. the stars on the U.S. flag).
Any figure or symbol placed on the field of a flag.
A coat of arms or simple heraldic symbol used as a charge.
A device used as a charge — heraldic or modern (e.g. the Canadian maple leaf).
A narrow edging or border (often white or gold) separating two other colours.
An emblem or charge added to an existing flag (e.g. arms on a state ensign).
Decorative cap atop the flagpole — sphere, spear, eagle, etc.
Loose fabric along the hoist used to attach a flag to its rope.
Vertical bisection of the field into two equal halves.
Horizontal bisection of the field into two equal halves.
Diagonal bisection from upper hoist to lower fly.
Diagonal bisection from upper fly to lower hoist.
A vertical band running down the centre of the field.
A horizontal band running across the centre of the field.
A diagonal band from upper hoist to lower fly.
A diagonal band from upper fly to lower hoist.
A horizontal band along the top edge of the field.
A horizontal band along the bottom edge of the field.
Three equal vertical bands (e.g. France).
Three equal horizontal bands (e.g. the Netherlands).
An X-shaped (diagonal) cross.
A symmetrical upright cross with arms of equal length.
An off-centre cross with the intersection toward the hoist.
Four equal rectangular quarters.
Generically any flag; in heraldry, a square flag matching a coat of arms.
A distinguishing pennant of a recreational boating organisation.
A version of a national flag flown on civilian installations or craft.
A national flag variant flown by civilian merchant ships.
A national flag variant restricted to government use, often the civil flag defaced with arms.
A national flag variant used by a nation's armed forces on land.
The flag of a ship or military unit — normally flown at the stern.
A flag flown from a short jackstaff at the bow of a ship.
A flag wider at the hoist than at the fly.
A heraldic flag suspended from a horizontal crossbar.
In heraldry, a long tapering flag bearing badges and motto; also a royal or military standard.
A small flag flown by a military unit; in Scottish heraldry, a smaller standard.
A flag-like object used symbolically but differing from a conventional flag.
A flag-like object suspended from a horizontal crossbar; the standard of the Roman army.
The flag of a military unit.
Flown by a visiting ship in foreign waters as a sign of respect.
Flag flown along Himalayan ridges to bless the surrounding land.
A flag hoisted to a position below the top of the pole as a sign of mourning.
Raising a flag up the pole.
The scholarly study of flags.
A person who designs flags.