# Unusual mathematical terms

From time to time, I come across some unusual mathematical terms. I know something about strange attractors. I also know what Witch of Agnesi is. However, what prompted me to write this question is that I was really perplexed when I read the other day about monstrous moonshine, and this is so far my favorite, out of similar terms.

Some others:

Are there more such unusual terms in mathematics?

Jan 17 update: for fun, word cloud of all terms mentioned here so far:

• I've always been tickled by 'Fuzzy Logic.' Jan 13, 2015 at 17:30
• The `Golden ratio' $\phi$.
– gone
Jan 13, 2015 at 17:37
• It may say more about me than about math, but if I need to give a strange sounding math term, then perverse sheaves is my go-to-answer. Jan 13, 2015 at 17:48
• Shouldn't this be CW? Jan 13, 2015 at 18:22
• “The question is widely applicable to a large audience. A detailed canonical answer is required to address all the concerns.” what. Jan 15, 2015 at 19:21

Telling a story on myself. When as a graduate student I first heard about noetherian rings (before I saw a definition) I wanted to know what an ether was, so I could think about a ring that didn't have any of them.

I later taught for a while at Bryn Mawr College, where a colleague used Emmy Noether's desk.

Game theory has a trembling hand, some cheap talk, and, collectively, an El Farol Bar problem.

In the Banach space theory there is a property called local unconditional structure, which is l.u.st for short. Another property is the Dunford-Pettis property which is DP for short.

Soap Film Problem - this is actually another term for "minimal surface problems", since soap bubbles or other similar soap forms tend to minimize their surface.

Also, Antoine's necklace.

Nice topology tool

The Tietze Extension Theorem is always a good one, and Heine-Borel if the speaker doesn't have his German pronunciations down.

I'm a big fan of Krylov Subspace Methods, which I remain convinced are actually ways of detecting cloaked Klingon birds of prey.

The Sieve of Eratosthenes is an abstract thing given a mundane (concrete) name, not unlike the "snowflake".  And I've heard that the term googol was chosen specifically because it sound funny.

John H. Conway and Simon B. Kochen's free will theorem

Free will theorem

And some theorems/terms named after unusual mathematicians. For example