What is Geeks-in-law?
1.
A way to describe your relationship with somebody who you originally met doing a geeky hobby (such as trainspotting, roleplaying or a science fiction fanclub), whether you still participate in that hobby or not.
It is a good way to answer awkward questions without having to, for example, describe to your new girlfriend what Magic: The Gathering is.
"Where did you guys meet"
"We're geeks-in-law"
See