Glossary of vexillology

Flag terminology is the nomenclature, or system of terms, used in vexillology, the study of flags, to describe precisely the parts, patterns, and other attributes of flags and their display.

Flags often inherit traits seen in traditional European heraldry designs and as a result patterns often share names.

(couped cross)

Flag illustrations generally depict flags flying from the observer's point of view from left to right, the view known as the obverse (or "front"); the other side is the reverse (or "back"). There are some exceptions, notably some Islamic flags inscribed in Arabic, for which the obverse is defined as the side with the hoist to the observer's right.

A vexillological symbol is used by vexillologists to indicate certain characteristics of national flags, such as where they are used, who uses them, and what they look like. The set of symbols described in this article are known as international flag identification symbols, which were devised by Whitney Smith.

Some countries use a single flag design to serve as the national flag in all contexts of use; others use multiple flags that serve as the national flag, depending on context (i.e., who is flying the national flag and where). The six basic contexts of use (and potential variants of a national flag) are:

In practice, a single design may be associated with multiple such usages; for example, a single design may serve a dual role as war flag and ensign. Even with such combinations, this framework is not complete: some countries define designs for usage contexts not expressible in this scheme such as air force ensigns (distinct from war flags or war ensigns, flown as the national flag at air bases; for example, see Royal Air Force Ensign) and civil air ensigns.

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