ʻO ka mīkini ʻōwili kahi ʻano mea hana e hoʻohana i nā ʻōwili hana e kulou a hoʻohua i ka mea pepa. Hiki iā ia ke ʻōwili i nā papa metala i loko o ka pōʻai, arc a me nā mea hana conical i loko o kahi ākea. He mea hana nui loa ia. ʻO ke kumu hana o ka mīkini paʻi paʻi e hoʻoneʻe i ka ʻōwili hana ma o ka hana o nā mana o waho e like me ke kaomi hydraulic a me ka ikaika mechanical, i ʻōwili ʻia a ʻōwili ʻia paha ka pā.
ʻO ka mīkini'ōwili he nui nāʻano o nā noi, a hiki ke hoʻohanaʻia i nāʻoihana o ka mīkini hana e like me nā moku, petrochemical, boilers, hydropower, pressure vessels, pharmaceuticals, papermaking, motors and electrical appliances, and food processing.