τ (EN)

letter, symbol

letter “τ”

1. the 19th letter of the Greek alphabet
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   In the Greek word for "life," the letter τ is used to represent the "t" sound.

symbol “τ”

1. (in physics) torque, a measure of the force that causes an object to rotate
   The engineer calculated the torque τ needed to turn the gear mechanism.
2. (in physics) shear stress, the force per area causing layers to slide past each other
   The material's deformation was analyzed by applying the shear stress τ.
3. (in mathematics) a constant equal to 6.283, representing the ratio of a circle's circumference to its radius
   By using τ instead of 2π, the formula for a circle's circumference becomes simpler.
4. (in physics) optical depth, a measure of how opaque a medium is to radiation
   Scientists measured the optical depth τ to understand the atmosphere's effect on starlight.
5. (in physics) the tau particle, an elementary particle similar to an electron but heavier
   The researchers observed the decay of the tau lepton τ in their experiments.
6. (in phonetics) a symbol representing a voiceless dental plosive sound
   In some phonetic scripts, τ denotes the dental 't' sound found in certain languages.
7. (in phonetics) a symbol representing a voiced coronal click consonant
   Linguists use τ to represent specific click sounds in the study of African languages.