Symbol:	Meaning:
$i,j,k,l=1,2,3$	spatial components of Einstein’s summation or notation, or Index/Subscript/Tensor notion
$T_{ij}$	an element of the Cauchy stress tensor $\mathit{T}$ $[N/m^2]\in {\mathbb{R}}^{3x3}$
$b_i$	an element of the body force vector $\mathit{b}$ $[N/m^3]\in {\mathbb{R}}^{3x1}$
$f_i$	an element of the surface force vector $\mathit{f}$ $\left[N\right]\in {\mathbb{R}}^{3x1}$
$E_{ij}$	an element of the strain tensor $\mathit{E}$ $\in {\mathbb{R}}^{3x3}$
$n_j$	an element of the unit normal vector $\mathit{n}$ $\in {\mathbb{R}}^{3x1}$
$\rho$	a density $[g/m^3]\in {\mathbb{R}}^1$
$X_i$	an element of the material point $\mathit{X}$ $\left[m\right]\in {\mathbb{R}}^{3x1}$ [494] (p. 61)
$x_i$	an element of the spatial point $\mathit{x}$ $\left[m\right]\in {\mathbb{R}}^{3x1}$ [494] (p. 61)
$F_{ij}$	an element of the deformation gradient $\mathit{F}$ $\in {\mathbb{R}}^{3x3}$
$u_i$	an element of the displacement vector $\mathit{u}$ $\left[m\right]\in {\mathbb{R}}^{3x1}$
$C_{ijkl}$	an element of the stiffness tensor $\mathbb{C}$ $[N/m^2]\in {\mathbb{R}}^{3x3x3x3}$
W	the strain-energy density function $\left[J\right]\in {\mathbb{R}}^1$
t	the time $\left[s\right]\in {\mathbb{R}}^1$
$\theta$	the temperature $\left[K\right]\in {\mathbb{R}}^1$
$\mathsf{\Delta }{\theta }_i$	an element of the temperature gradient $\mathsf{\Delta }\mathbf{\theta }$ $[K/s]\in {\mathbb{R}}^{3x1}$
$\xi$	an unknown internal variable $[?]\in {\mathbb{R}}^{?}$
Y	a unidirectional Young’s Modulus $[N/m^2]\in {\mathbb{R}}^1$