We admit...

Given the choice, we'd rather have an M9 than an M3.

VAT

V.A.T. can stand for value added tax or for view angle tilting.

"F.A."

In MRI, "F.A." (often written without periods, as "FA") can stand for either flip angle, which measures how much of the refractory longitudinal magnetization is converted into detectable transverse magnetization, or fractional anisotropy, which expresses the degree to which the diffusion of water is directionally non-uniform.

ROI - ACC

To most of my colleagues, ROI means "region of interest", a connected collection of pixels on a radiological image, and ACC means "anterior cingulate cortex", an interesting and important part of the brain (comprising Brodmann areas 24 & 32). But.

In the world of business, ROI means "return on investment", ACC means "average cost of capital", and their difference, ROI - ACC, means profit. Or loss.

The "WM" bits can be white or grey.

In neuroscience & neuroimaging, "WM" can refer either to white matter or to working memory.

Do you mostly hang out with WEIRDos?

In their paper "The weirdest people in the world?", Joseph Henrich, Steven J. Heine and Ara Norenzayan argue that:

1. The scientific literature in the field of experimental psychology consists primarily of reports of experiments upon subjects who were handy and willing – namely, college undergraduates, who are "Western, Educated, Industrialized, Rich, and Democratic (WEIRD)".
2. "...WEIRD subjects are particularly unusual compared with the rest of the species – frequent outliers ... [in] domains ... includ[ing] visual perception, fairness, cooperation, spatial reasoning, categorization and inferential induction, moral reasoning, reasoning styles, self-concepts and related motivations, and the heritability of IQ."
3. "...we need to be less cavalier in addressing questions of human nature on the basis of data drawn from this particularly thin, and rather unusual, slice of humanity."

AED

AED can stand for Automated External Defibrillator or Anti-Epileptic Drug.

eV & EV

An eV is an electron Volt; an EV is an Exposure Value.

TTL

"TTL" means both "transistor-transistor logic" (& associated voltage levels for logic signals) as well as "through the lens" metering for flash photography.