http://mentalfloss.com/article/54486...family-members

the above link takes you to a website where you see 11 words and their definitions. So how can these be used in the world of soap?

I can't think of any double cousins, which is surprising given the amount of double relations.

Patruel - Child of paternal uncle. Any of the Slater sisters and Zoe.

Half brother from same mother: EE - Danielle/James, Zoe/Tommy, Sonia or Bianca and Robbie or Billie, or Robbie and Billy. Ronnie or Roxy and Danny.

ED - Cain and Chas

Machetonim - CS Gail and Eileen! (at one time anyway)

Other Brother-Uterine relationships (Half brother from same mother) Nick/Sarah & David (Corrie), Ben & Ian (EE), Jason & Todd (Corrie), Leanne & Eva (Corrie)

Adam Barton is cousins and siblings with Holly and Hannah Barton isn't he?

He is indeed, making them three quarter siblings (as James and John are full siblings) rather than double cousins. For Adam and Holly and Hannah to be double cousins, his mother would need to be a full sibling of Moira.

Debbie Dingle must be daughter AND cousin with Cain Dingle and visa versa with Charity Macey?

This is true, same for Lexi Pearce with Ben Mitchell and Lola Pearce on EE, although different degrees of cousins.

I think Cain and Charity are first cousins, making them both first cousin once removed of Debbie and Debbie second cousin to herself.

Sarah Sugden is related to charity and cain but must also be their cousin?

Does anyone know?

Sarah Sugden as in Debbie and Andy's daughter? She would be their granddaughter and first cousin twice removed. She is also Debbie's second cousin once removed as well as her daughter.

This is hurting my head.

Liam Butcher and Pat Evans...

Great Grandmother.
Step Grandmother.

Hollyoaks: Joe, Freddie and Ziggy Roscoe are brother-uterines of Darren, Robbie and Jason (And vice-versa.) As are Dodger and Sienna with Will. As are Mandy and Lewis with Tom. As are (sort-of) Sinead and Finn with Ant and Dee.

EE: Amy Mitchell and James Branning are/were 3/4 siblings and full cousins with the same father, and mothers who are full sisters.

Rebecca Fowler is Bianca's (half) niece and cousin twice removed through Sonia and Martin, making her Liam, Tiffany and Morgan's (half) cousins and first cousins thrice removed.

Derek, Max and Jack are the avuncles or eames of Bianca, Sonia, Robbie, Billie, Kevin and Rebecca (Branning); while

April, Carol and Suzy are the amitas of Bradley, Joey, Alice, Lauren, Abi, Oscar, Penny, Amy, James and Richard.

David's stepbrother Ricky was also is son-in-law!

And many more... !