What Greek letters do we use?

In My Humble Opinion
1

Ignoring fraternities or sororities since they just use the Greek letter itself, it has no other meaning.

I think Pi is the most common being a basic part of math.

Alpha gets used in the sense of “first” like alpha male or female, plus meaning “letters” as opposed to numbers, like alphabet or alpha-numeric.

Most people today would understand Beta testing.

Delta in the definition of a river delta or mathematically meaning “change”. Delta T is change in temperature, Delta t is change in time. DT/Dt is, well - something.

Gamma - gamma rays, of course, although I might think of “gamma seals” first - every survivalist’s favorite gadget to turn the common five gallon pail into a hermetically sealed container - although probably unknown to many people.

Omega meaning “end” or “the last” like Omega Man or alpha-omega.

Any others in common use?

2

Each and every one of them, it seems.

3

Also common in baking.
:flees:

4

For Atlantic tropical storms and hurricanes, if they run out of latin alphabetical names they switch over to greek letters. In 2005 they got all the way to tropical storm zeta. And so far this year the storms have been forming even faster than 2005.

5

Just to be cleat though, zeta is the 6th letter of the Greek alphabet not the last; alpha, beta, gamma, delta, epsilon, zeta.

6

I still see iota in crossword puzzles, usually related to the phrase “every iota and jot”.

7

… Although to be honest, I don’t think F is in ‘common’ use by any measure.

8

The question isn’t, however, which Greek letters have been used at one time or another for some mathematical or scientific concept, and but which are in “common use.” Only a few of them are, so the link doesn’t serve to answer the question.

9

They missed kappa omega and kappa epsilon turbulence models used in computational fluid dynamics.

10

Aside from the ones mentioned in the OP and iota, possibly the most common one is psi, representing psychic powers in parapsychology.

11

But remember, pie are not square, pie are round.

12

I ran across sigma a lot in Calculus class and probability studies.

There’s some relationship between Tau something and Alzheimer’s Disease in a lot of the news articles I’ve read.

Whether either of those counts as ‘we use’ status, dunno.

13

Those who use Microsoft Excel might use sigma. And doesn’t mu represent the sound a cow makes?

14

Both alpha and beta are used a lot to refer to software that isn’t fully ready. Beta came first, and meant something like “test version.” And then some versions were considered not even good enough for that, so they got labeled “alpha.”

Since then, other names have popped up, like “nightly” (meaning newly compiled once a day), “canary” meaning “problems will show up first here” and “dev” or “development” meaning “only ready for developers to use.” So “alpha” hasn’t been used as much. But “beta” is still used a lot.

“Iota” is still in use from the Biblical allusion, saying “not one iota of it can change.” It comes from Hebrew and that fact that their “i” vowel is just a dot. When translated to Greek, they used “iota,” which is the same sound and just a single line. So not even the slightest dot or line will be changed.

In the metric system, mu is used as the abbreviation for micro, because m was already taken for milli. Soemtimes it gets replaces with just a u or mc, though.

If we keep pi from math, then I think sigma is similarly popular enough to count. It’s used in summation notation. I’ll also throw in an honorable mention for tau, which looks like pi with only one leg, and has been pushed as a replacement for 2 * pi. Phi is another rather common mathematical constant like pi, referring to the golden ratio.

And Omega can be used along with Alpha to mean the end to Alpha’s beginning, This is also probably a Biblical reference.

Those are the terms I’m familiar with, anyways. I know other mathematical things, like zeta for the zeta function, capital Pi for products, epsilon for a very small quantity, and such, but I don’t think those count as common enough.

Edit: Forgot about psi, which Colibri mentioned.

15

I actually hear most English speakers pronounce it “myoo” instead of “moo.” So it would be the sound a kitten makes.

16

Mu is used in SI for the prefix micro- (since m is milli-, and M is mega-). The most commonly used micro- unit is probably the micrometre.

17

I was at the airport in Hong Kong waiting for my flight and had some time to kill. I wandered around the terminal after going through the security check. There was a very good display of works by local artists. One work was a big plexiglass Greek letter π filled with wax apples. You already know the work’s title.

18

I’ve seen the term “beta” used to refer to people (mostly males) who are shy, introverted, and basically the opposite of alpha males.

19

I’ve actually even heard gamma males in some instances. Unlike betas, they aren’t even interested in becoming alpha.

Of course, all of this comes from a messed up interpretation of how wolves and dogs operate. They thought they formed a hierarchy because they would bring in a bunch of animals who didn’t know each other. But, in the wild, they tend to form family units, and what can pass as a leader is often a matriarch.

20

Isn’t theta used in some way in scientology? Lambda used to be a pretty common sort-of-secret reference to being gay, before gay lib, I don’t know what the status is these days.