Absolute convergence of orthogonal series.- Absolute Nörlund summability almost everywhere of fourier series.- Absolute Nörlund summability almost everywhere of orthogonal series.- Absolute Riesz summability almost everywhere of orthogonal series.- Absolute Nörlund summability factors of fourier series.- Absolute Nörlund summability factors of conjugate series of fourier series.- Local property of absolute Riesz summability of fourier series.- Local property of absolute Nörlund summability of fourier series.