マンション

Borrowed from English mansion.[1][2] The term gained currency in the latter half of the 1950s, used to lend an air of luxury to high-density residential development projects.[3]

Note that while English mansion most commonly means “large house”, it is also occasionally used to mean “luxurious apartment”, and this latter usage was borrowed into Japanese.

• (Tokyo) マ​ンション [máꜜǹshòǹ] (Atamadaka – [1])[2]
• IPA^(key): [mã̠ɰ̃ɕõ̞ɴ]

マンション • (manshon) 

1. a condominium
2. an apartment building
3. a large apartment; a large flat

• The term マンション (manshon) contrasts with アパート (apāto) in that the former is more commonly a condominium as a flat or apartment that is owned as a piece of real estate, whereas the latter is more commonly a flat or apartment that is rented or leased.

• アパート (apāto, “rental flat or apartment”)

• 億(おく)ション (okushon): a high-end condominium
• 高級(こうきゅう)マンション (kōkyūmanshon): a high-class condominium