The phrase "narrow stairs" refers to a staircase that is not very wide. It means that the stairs are slim and have limited space for people to walk on.
Sentences with «narrow stairs»
A multi-stripe design will make narrow stairs in a country cottage seem wider. (idealhome.co.uk)
Aching legs are being commanded up narrow stairs cutting into the steep mountainside. (theexpeditioner.com)
We have narrow hallways with narrow stairs and lots of dogs around. (thatmutt.com)