Where the thingamajig fits.    

I know this one :) mortise and tendon

a hole ready for reception to cause a pinning!

I have no idea!

Is the first name "Riga"?  ....Riga Mortise?  Could be the name of a stiff drink!  

The receiving cavity, half of a great technique for nailess joints in woodworking. BTW the part that fits into the mortise is a tenon not a tendon. Reading some answers I thought people were joking about body parts 

It is something I don't know about. 

Now you are talking my husband's language. He has sold commercial grade locks and installed them for almost 50 years and I have gotten many lessons on the mortise cylinder and why this is a preferred product over the cheaper locks.

It's when an alluring young lady teases Morty.

That is the great big grand-daddy of a tortoise. 

Mortise the tortise?

What you stick a tendon into.

I find this to be gluttony. One 'Tise' is enough Mortise is just plain fattening.

A craft that has gone by the wayside!

That is in the teenage mutant ninja movie this summer.

Glueless or nailess structures used in Chinese imperial courts.

Interesting - I didn't know this one - we have some very smart people here - or ones who google first and then answer  LOL

Also used in woodworking

a cavity cut into wood to hold a tenon.... a joint....

I'm with Wayne & Michael describes it just like I do.

Tony and Suzanne Marriott, Associate Brokers Commonly used when permanently joining two pieces together. A tendon is formed on one piece and the other a mortise allowing the two pieces to be joined together.

A place to put a tennon

No idea.