def segmentSpecificKeyword(keyword_root, segment):
    """Construct a segment-specific keyword.

    Parameters
    ----------
    keyword_root: str
        The part of the keyword name preceding the segment-specific
        character.

    segment: str
        Segment or stripe name

    Returns
    -------
    str
        Keyword (lower case) for the specified segment.
    """
    keyword_root = keyword_root.lower()
    if segment[0] == 'F':
        key = keyword_root + segment[-1].lower()
    else:
        key = keyword_root
    return key
