TITLE: Who coined "mob" and "clan" and why these words?
QUESTION [6 upvotes]: A mob is a word used for a topological semigroup which is a Hausdorff space. A clan is a compact connected mob with a two-sided identity element.
Who used these words with these meanings first and when? Why were these words chosen? I'm guessing it's a play on "group", but is it really?

REPLY [8 votes]: The mob/clan terminology goes back to Alexander Wallace:

A note on
mobs (1952).
The
structure of topological semigroups (1953).