staircase
The given information is incorrect. 'Estanco' does not translate to 'staircase'. 'Estanco' is a Spanish word which is generally used to represent a small shop or kiosk that sells tobacco, stamps, and other public documents in Spain. Sometimes it could also mean a place where the sale of an item is strictly controlled by the state or 'a monopoly'. A closer Spanish word for 'staircase' is 'escalera'.
I smoke a lot and always buy my cigarettes at the tobacco shop.
In this example, 'estanco' is used to refer to a shop that specifically sells tobacco products, like cigarettes.
The nearest tobacco shop is two blocks away from here.
Here, 'estanco' is used to describe a place where one can buy tobacco and other similar goods. The phrase indicates the location of the nearest such establishment.
Let's go to the tobacco shop to buy stamps to send these letters.
In this sentence, 'estanco' is referring to a tobacco shop where, apart from tobacco, it is common to buy other items like stamps in Spain.