Vexillological symbols are used by vexillologists to indicate certain characteristics of flags, such as where they are used, who uses them, and what they look like. The symbols were created by vexillologist Whitney Smith and then adopted by the International Federation of Vexillological Associations (FIAV) in the early 1970s. Vexillologist Željko Heimer added the symbols for normal and historical in the early 1990s.
Status and design symbols
Vexillological symbols describe information on a flag's recognition status and design.
{| class="wikitable sortable sticky-header"
|+ style="text-align: left;" | List of symbols
!Symbol
!Meaning
|-
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| Normal or de jure version of flag, or obverse side
|-
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|Design was proposed in the past, but never officially adopted
|-
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|Design is a reconstruction, based on past observation
|-
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|Reverse side of flag
|-
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|An acceptable variant of the standard flag
|-
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|One of several alternative versions of the flag that can be displayed
|-
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|De facto flag, widely accepted and used
|-
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|Flag has different designs on its obverse side and its reverse side
|-
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|Obverse side meant to be hoisted with pole to the observer's right
|-
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|Design officially authorized to represent nation by government of that nation (not necessary to use when the de jure symbol is used)
|-
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|Design used in the past, but now abandoned
|-
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|Reverse side is mirror image of obverse side
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|Reverse side is congruent to the obverse side
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|Information on reverse side is not available
|-
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|Flag can be hung vertically by hoisting on a normal pole, then turning the pole 90°
|-
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|Flag can be hung vertically by rotating the design first
|-
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|Vertical hoist method of flag is unknown
|-
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|Design has no element which can be rotated
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|Flag can only be hoisted vertically
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|Flag is not authorized to represent the group or country
|}
== Usage symbols ==<!-- This section is linked from List of Polish flags -->
The usage symbols are based on a grid of two rows representing use on land and use on water, and three columns representing private use, public use, and military use. Each circle in the grid indicates the flag has one or more of the following six basic usages:
{| class="wikitable sticky-header"|style="text-align: center;"
!
! scope="col" | Private
! scope="col" | Public
! scope="col" | Military
|-
! scope="row" | Land
|Civil flag
Flown by private citizens on land
|State flag
Flown by the government on land
|War flag
Flown by the military on land
|-
! scope="row" | Water
|Civil ensign
Flown by private vessels
|State ensign
Flown by government vessels
|Naval ensign
Flown by military vessels
|}
A single design may be associated with no usages or multiple usages. Heimer suggested an additional row for air ensigns, but it has not been adopted by FIAV. The air ensign row refers to flags displayed on aircraft, including when on the ground, and air installations. The air ensign row is placed above the remaining two rows.