A common term in music theory—the “cadential six-four” (or cadential $\left.\text{}^{6}_{4}\right.$)—is used to refer to the $\left.\text{I}^{6}_{4}\right.$ that regularly proceeds the $\left.\text{V}\right.$ chord in cadences.
It is worth remembering that the cadential $\left.\text{}^{6}_{4}\right.$ (or $\left.\text{I}^{6}_{4}\right.$) has dominant function, just like the $\left.\text{V}\right.$ chord that usually follows it. Previously, we have called this chord “$\left.\text{I}\middle/\text{5th}\right.$.”