Main Difference
The main difference between City and District is that the City is a large and permanent human settlement and District is a type of administrative division, in some countries.
City
A city is a large human settlement. Cities generally have extensive systems for housing, transportation, sanitation, utilities, land use, and communication. Their density facilitates interaction between people, government organizations and businesses, sometimes benefiting different parties in the process.
Historically, city-dwellers have been a small proportion of humanity overall, but following two centuries of unprecedented and rapid urbanization, roughly half of the world population now lives in cities, which has had profound consequences for global sustainability. Present-day cities usually form the core of larger metropolitan areas and urban areas—creating numerous commuters traveling towards city centers for employment, entertainment, and edification. However, in a world of intensifying globalization, all cities are in different degree also connected globally beyond these regions.
The most populated city proper is Shanghai while the largest metropolitan areas also include the Greater Tokyo Area and Jabodetabek (Jakarta). The cities of Faiyum, Damascus, and Varanasi are among those laying claim to longest continual inhabitation.
District
A district is a type of administrative division that, in some countries, is managed by local government. Across the world, areas known as “districts” vary greatly in size, spanning regions or counties, several municipalities, subdivisions of municipalities, school district, or political district.
City (noun)
A large settlement, bigger than a town.
“São Paulo is one of the largest cities in South America.”
City (noun)
A settlement granted special status by royal charter or letters patent; traditionally, a settlement with a cathedral regardless of size.
City (noun)
The central business district; downtown.
“I’m going into the city today to do some shopping.”
District (noun)
An administrative division of an area.
“the Soho district of London”
District (noun)
An area or region marked by some distinguishing feature.
“the Lake District in Cumbria”
District (noun)
An administrative division of a county without the status of a borough.
“South Oxfordshire District Council”
District (verb)
To divide into administrative or other districts.
District (adjective)
rigorous; stringent; harsh
City (noun)
a large town
“one of Italy’s most beautiful cities”
“the city council”
City (noun)
a town created a city by charter and usually containing a cathedral.
City (noun)
a municipal centre incorporated by the state or province.
City (noun)
a place or situation characterized by a specified attribute
“the staff were in turmoil—it was panic city”
City (noun)
short for City of London
City (noun)
the financial and commercial institutions located in the City of London
“the Budget got a stony reception from the City”
“a City analyst”