It consists of key value pair.

let devices: [String: String] = [

"phone": "iphone x",

"laptop": "2020 Macbook Air M1",

"Console": "Playstation 5",

]

first string is the key ie. phone, laptop, console

second string is value ie. iphone x, macbook air, playstation 5

only one key can be associated to one value

if u want one key to be associated to multiple value type like this

var items = ["apple", "banana", "orange"]

var shoppingCart: [String: [String]] = ["fruit": items]