DISCHRONIC - timeless

DIACONIC - conic section, e.g. ellipse, parabola

DIANOMIC - Double, double toil and trouble

DIAGONIC - (pronounced dia-GON-ic) - 'woke' term for diagonal (students complained that 'diagonal' sounds too much like 'agony')

DIIRONIC - doubly ironic, e.g. 'a thin lot of good' instead of 'a fat lot of good'