What is the name of this herb?

This is an Oregano plant. It is a very important culinary herb. It can be dried and in that form is very flavorful. The chemical compounds in the leaves such as carvacrol, thymol and limonene give it a unique taste. It is used extensively in Italian-American cuisine such as pizza and pasta. It is frequently used with roasted, fried, or grilled vegetables, meat, and fish. Oregano combines well with spicy foods popular in southern Italy. It is native to temperate western and southwestern Eurasia and the Mediterranean region. Oregano oil is a very potent folk medicine. It is claimed to be good for the digestive system.

Oregano is a perennial herb, growing from 20–80 cm (7.9–31.5 in) tall, with opposite leaves 1–4 cm (0.39–1.57 in) long. The flowers are purple, 3–4 mm (0.12–0.16 in) long, produced in erect spikes. While it is a perennial, it often is grown as an annual in locations where the temperatures are colder. You likely have some of the dried leaves in your spice/herb collection.