def interpret_wcsname_type(wcsname):
    """Interpret WCSNAME as a standardized human-understandable description """
    wcstype = ''
    fit_terms = {'REL': 'relatively aligned to {}', 'IMG':
        'aligned image-by-image to {}', 'SVM': 'aligned by visit to {}'}
    post_fit = 'a posteriori solution '
    default_fit = 'a priori solution based on {}'
    base_terms = {'IDC': 'undistorted ', 'OPU': 'pipeline default '}
    no_fit = 'not aligned'
    wcsname = wcsname.upper()
    wcsname_list = wcsname.split('-')
    wcsname_term = wcsname_list[0][:3]
    if wcsname_term not in base_terms:
        wcstype = 'user-defined'
        return wcstype
    wcstype += base_terms[wcsname_term]
    fit_term = wcsname_list[1] if len(wcsname_list) > 1 else None
    if len(wcsname_list) == 1:
        wcstype += no_fit
    elif 'FIT' not in fit_term:
        wcstype += default_fit.format(fit_term)
    else:
        wcstype += post_fit
        postfit_type = fit_term.split('_')
        wcstype += fit_terms[postfit_type[1]].format(postfit_type[2])
    return wcstype
