One of the mysteries of the English language finally explained.

# Definition of *Peclet number* in US English:

## Peclet number

(also

**Péclet number**)### noun

PhysicsA dimensionless parameter used in calculations of heat transfer between a moving fluid and a solid body, representing the ratio of the convected to the conducted heat and equal to the product of the Reynolds number and the Prandtl number, viz. Dvcp/k, where D is a characteristic length of the body, v is the speed of the fluid past it, cp is the heat capacity of unit volume of the fluid at constant pressure, and k is its thermal conductivity. Abbreviated Pe.

**Origin**

1930s. From the name of J. C. E. Péclet, French physicist + number.