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Glossary of Documentation Terms
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.. glossary::

    (`n`,)
        A parenthesized number followed by a comma denotes a tuple with one
        element. The trailing comma distinguishes a one-element tuple from a
        parenthesized ``n``.
        This is from NumPy; see https://numpy.org/doc/stable/glossary.html.

    number
        Any numeric type. eg float or int or any of the ``numpy.number``.

    -like
        Used to indicate on object of that type or that can instantiate the type.
        E.g. :class:`~astropy.units.Quantity`-like includes ``"2 * u.km"``
        because ``astropy.units.Quantity("2 * u.km")`` works.

    unit-like
        Must be an :class:`~astropy.units.UnitBase` (subclass) instance or a
        string or other instance parseable by :class:`~astropy.units.Unit`.

    quantity-like
        Must be an `~astropy.units.Quantity` (or subclass) instance or a string
        parseable by `~astropy.units.Quantity`.
        Note that the interpretation of units in strings depends on the class --
        ``Quantity("180d")`` is 180 **days**, while ``Angle("180d")`` is 180
        **degrees** -- so check the string parses as intended for ``Quantity``.

    angle-like
        :term:`quantity-like`, but interpreted by an angular
        `~astropy.units.SpecificTypeQuantity`, like `~astropy.coordinates.Angle`
        or `~astropy.coordinates.Longitude` or `~astropy.coordinates.Latitude`.
        Note that the interpretation of units in strings depends on the class --
        ``Quantity("180d")`` is 180 days, while ``Angle("180d")`` is 180 degrees
        -- so make sure the string parses as intended for ``Angle``.

    length-like
        :term:`quantity-like`, but interpretable by
        :class:`~astropy.coordinates.Distance`.

    frame-like
        A :class:`~astropy.coordinates.BaseCoordinateFrame` subclass instance or a
        string that can be converted to a Frame by
        :class:`~astropy.coordinates.sky_coordinate_parsers._get_frame_class`.

    coordinate-like
        A Coordinate-type object such as a
        :class:`~astropy.coordinates.BaseCoordinateFrame` subclass instance or a
        :class:`~astropy.coordinates.SkyCoord` (or subclass) instance.

    table-like
        An astropy :class:`~astropy.table.Table` or any object that can
        initialize one. Anything marked as table-like will be processed through
        a :class:`~astropy.table.Table`.

    time-like
        :class:`~astropy.time.Time` or any valid initializer.

    buffer-like
        Anything that implements Python's buffer protocol. See
        https://docs.python.org/3/c-api/buffer.html#bufferobjects

    writable file-like object
        In the context of a :term:`python:file-like object` object, anything
        that supports writing with a method ``write``.

    readable file-like object
        In the context of a :term:`python:file-like object` object, anything
        that supports writing with a method ``read``.