umbraced used when the arm is completely covered with armour (see vambraced)

umbrated or adumbrated shadowed

undé a line of partition formed like waves (see ondé and wavy)

unguled used of animals hooves when they are coloured differently from the body

urchin a hedgehog

uriant used of a fish when shown with the head downwards and the tail erect

urvant or urved turned or bowed upwards