A subdistrict is an administrative division which is one level lower than a district.
Usage by country
In Bangladesh, subdistricts are known as upazilas. They are the third-level and the second lowest-level subdivisions, below divisions and zilas (districts).
In Brunei, subdistricts are known as mukims and they are the second-level country subdivision, immediately below districts (daerah). Mukims are subdivided into villages (kampung).
In Mainland China, a subdistrict (Chinese: 街道; pinyin: jiēdào) literally means "streets (Chinese: 街; pinyin: jiē; lit.: 'east-west public thoroughfare') and avenues (Chinese: 道; pinyin: dào; lit.: 'north-south public thoroughfare')".
In East Timor, a subdistrict is known by the Portuguese word subdistrito.
In India, Census India calls the units below the district (जिला) and they are usually called subdivisions (अनुमंडल), tehsil (sometimes referred C D blocks प्रखंड), (taluk/ taluka / mandal) accordingly administrative divisions of india.
In Indonesia, subdistrict refers to kelurahan, which has same level with village.
In Israel, a subdistrict is known in Hebrew as nefa.
In Palestine, a subdistrict is known in Arabic as qadaa.
In Thailand, the equivalent of a subdistrict is a tambon.
In England and Wales, subdistrict was part of a registration district.
Kaza was the Turkish term for subdistricts during the Ottoman Empire.