U is for
Ukete 受け手
'receiver' This term is used for someone who is being tied, it is taken from martial arts where it is used to describe someone who a move is being used on - the person being thrown/hit etc.
Uranodome 裏の留め
Ura (裏) means back or reverse side, and as such this can be translated as either reverse or backside of a nodome. Some people use this to describe a nodome that has been tied with the face that is normally against the skin upwards, while others use this to describe a nodome which is tied so that the wrap sits on top of the band instead of under it. It is sometimes incorrectly refered to by English speakers as a reverse munter hitch.
Upline
A rope which is used to suspend some, going up from the body to the hardpoint.
Usagi shibari 兎縛り
'rabbit binding' a tie in which the hands are placed behind the head making the elbows look like rabbit ears.
Ushirote gasshō shibari 後手合掌縛り
'hands tied behind the back in prayer position' .