The flat area of flooring usually at a right angle to the top of a staircase leading to rooms.
The vertical infill between the handrail and baserail (or the tread if on open string stair).
Closed string staircase
When a stair has a closed string, the treads and risers are housed inside the string, with no visible outside profile.
Runs parallel to the handrail at the base of the spindles.
The vertical part of a step.
The top or horizontal surface of a step.
The large post that fits at the beginning and end of a staircase and supports the handrail.
Set on top of the newel post.
Open string staircase
A string where the upper edge follows the shape of the treads and risers. Here the steps can be seen in profile.
This runs diagonally with the pitch of the stairs on top of the spindles.
Half newel post
The large post that fits against the wall on the landing.
Part two of our terminology guide can be found here.