#### Description:

This attribute specifies a short-form symbol to be used to represent coordinate values for a particular axis of a Frame. This might be used (e.g.) in algebraic expressions where a full description of the axis would be inappropriate. Examples include `"` RA`"` and `"` Dec`"` (for Right Ascension and Declination).

If a Symbol value has not been set for a Frame axis, then a suitable default is supplied.

Type:

  String.

#### Applicability

##### Frame

The default Symbol value supplied by the Frame class is the string `"` < Domain > <n >`"` , where <n > is 1, 2, etc. for successive axes, and <Domain > is the value of the Frame`’` s Domain attribute (truncated if necessary so that the final string does not exceed 15 characters). If no Domain value has been set, `"` x`"` is used as the <Domain > value in constructing this default string.

##### SkyFrame

The SkyFrame class re-defines the default Symbol value (e.g. to `"` RA`"` or `"` Dec`"` ) as appropriate for the particular celestial coordinate system being represented.

##### TimeFrame

The TimeFrame class re-defines the default Symbol value as appropriate for the particular time system being represented.

##### FrameSet

The Symbol attribute of a FrameSet axis is the same as that of its current Frame (as specified by the Current attribute).

#### Notes:

- When specifying this attribute by name, it should be subscripted with the number of the Frame axis to which it applies.

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