Electoral districts go by different names depending on the country and the office being elected.
Argentina
The 257 members of the Chamber of Deputies are elected by proportional representation in 24 multi-member constituencies based on the provinces (plus the Autonomous city of Buenos Aires). Each one has a minimum of 5 seats and a maximum of 70.
For the 72 members of the Senate, each province (plus the City of Buenos Aires) has a fixed number of three senators.
Armenia
Beginning with the 2017 parliamentary election, the Armenian National Assembly elects members by proportional representation. Half the seats are filled from closed national party lists. The other half are chosen from 13 electoral districts allowing open list voter choice. As seat distribution is calculated at the national level, each electoral district is not guaranteed to return a specific number of seats. Each marz is coterminous with an electoral district with the exceptions of Vayots Dzor and Syunik (which are merged into one) and the Yerevan capital region, which is divided into 4 electoral districts.
Australia
In Australia, federal constituencies are officially termed divisions, and their state counterparts electoral districts. At both levels, though, they are popularly referred to as electorates or seats.
Bangladesh
Bangladesh has 300 parliamentary constituencies. There is one member of Parliament for each constituency. According to the constitution, the 50 seats reserved for women are allocated to the political parties according to their proportional representation.
Barbados
Barbados has 30 parliamentary constituencies. Some constituencies cover entire parishes while some parishes contain multiple constituencies depending on the population. Each constituency has a seat which is occupied by a representative who sits in the House of Assembly (the lower house) as a member of parliament. Prior to 1971, there were once dual representatives for each constituency instead.
Belgium
Bosnia and Herzegovina
Botswana
Botswana has 57 parliamentary constituencies. There is one member of Parliament for each constituency.
Brazil
In Brazil, seats in the lower chamber of the National Congress (Câmara dos Deputados) are split throughout the 26 States and the Federal District in a roughly proportional manner; however, a guaranteed minimum of 8 seats and maximum of 70 per federal entity means voters in Roraima have more than 8 times the representation as voters in São Paulo. The States of São Paulo and Minas Gerais have the largest number of seats. Within each federal entity, representatives are chosen by open-list proportional voting.
For the senate, each federal entity (state or federal district) has a fixed number of three senators. Each quadrennial election alternates between electing one and two senators per federal entity.
Bulgaria
In Bulgaria there are 31 constituencies arranged so as to coincide with the administrative division of Bulgaria, with the exception of Sofia City and Plovdiv provinces, where there are 3 additional constituencies (Sofia City is divided into 3 constituencies and Plovdiv is divided into 2). They are numbered according to their alphabetical order in Cyrillic.
Experimentally in the 2009 Bulgarian parliamentary election, 31 out of the 240 Members of Parliament were elected by majority vote, while the remaining 209 were elected by proportional vote. This mixed electoral system was rejected later.
Canada
In Canada, constituencies are legally known as electoral districts (in French, circonscriptions) for Members of Parliament; and Members of Legislative Assemblies or Members of Provincial Parliament (Ontario), Members of the National Assembly (Quebec), or Members of the House of Assembly (Newfoundland and Labrador) at the provincial level, although "constituency" and the informal term "riding" (or "comté" in French) are also used.
Chile
Chile's bicameral Congress consists of a Chamber of Deputies (lower house) and a Senate (upper house). The country is divided into 28 electoral districts for the lower house and 15 senatorial constituencies for the Senate. Each electoral district elects between 3 and 8 deputies and each senatorial constituency elects 3, 4 or 5 senators; there are 155 deputies and 43 senators in total. From 2022 the number of senators will increase to 50 because only the half of the senators are elected every election. Before the 2017 election, both seats in two-seat electoral districts were filled in the same election; after 2017, there are plurinominal districts.