A perfect witty remark, retort, or rejoinder that occurs to one after the fact or too late to be used. I was on the bus home long after being tongue-lashed by my boss when I thought of the perfect things to say that would take him down a few pegs. Ah, this staircase wit, it always comes to me when I can do nothing about it!

dated In the basement or on the bottom floor of a house, which was once the floor commonly inhabited by servants. All of the servants need to be below stairs before the lord of the manor returns.

old-fashioned To rain extremely heavily. Primarily heard in UK. We've been preparing for this match for weeks, but I heard it's going to be raining stair-rods tomorrow. We were looking forward to sunny skies in Portugal, but it rained stair-rods the whole time we were there.

An expression of surprise. Primarily heard in UK. Well, I'll go to the foot of our stairs—I had no idea you were planning on giving me that big award! You two are sisters? Wow, I'll go to the foot of our stairs!