how array can be object and array at the same time?

Question

code:-

let a = [1,2,3,4,5]
console.log(a)
console.log("type of a:-",typeof(a))
console.log("isArray a:-",Array.isArray(a))

note:- i ran it on chrome output:- (5) [1, 2, 3, 4, 5] type of a:- object isArray a:- true

i was checking Array is object or just array but it is showing it is array and object at the same time