tau

noun

ˈtau̇  ˈtȯ 

1

: the 19th letter of the Greek alphabet see Alphabet Table

2

: a short-lived elementary particle of the lepton family that exists in positive and negative charge states and has a mass about 3500 times greater than an electron

called also tau particle

3

: a protein that binds to and regulates the assembly and stability of neuronal microtubules and that is found in an abnormal form as the major component of neurofibrillary tangles

Examples of tau in a Sentence

Recent Examples on the Web

The test calculates a ratio of two proteins, tau and amyloid, found in blood plasma. —Ken Alltucker, USA Today, 16 May 2025

Anti-herpetic tau preserves neurons via the cGAS-STING-TBK1 pathway in Alzheimer’s disease Michigan State University. —Jack Knudson, Discover Magazine, 2 May 2025

Slower growth of proteins that harm the brain: Statins may interfere with the growth of amyloid-beta and tau, proteins linked to dementia and Alzheimer’s. —Emily Kay Votruba, EverydayHealth.com, 4 Apr. 2025

Researchers are also homing in on tau by actively testing treatments that could remove abnormal clusters of these proteins in mice, as well as methods that might potentially prevent tau from tangling up in the brain to begin with. —Alisa Hrustic, SELF, 24 Mar. 2025

Word History

Etymology

Middle English taw, from Latin tau, from Greek, of Semitic origin; akin to Hebrew tāw taw

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing tau

• tau cross

Kids Definition

tau

noun

ˈtau̇ 

ˈtȯ

: the 19th letter of the Greek alphabet

—Τ or τ

Medical Definition

tau

noun

ˈtau̇  ˈtȯ 

: a protein that binds to and regulates the assembly and stability of neuronal microtubules and that is found in an abnormal form as the major component of neurofibrillary tangles

called also tau protein