Rkay : I think I'd just use 'potholes' to describe what today's word is calling 'thank-you-ma'am's'
Oh dearie me no!
A pothole is a hole in the road usually caused when winter frost heaves subside. At least in cold winter areas.
Re thank-you-ma'ams : In my youth secondary roads were not as beautifully graded as they are now ... and sometimes as you went along the car would come to a raised section of road with sloping sides - large enough to tilt the car up and down again quite quickly - but not high enough to "hang it up."
Have you ever been in an airplane when it "hit an air pocket" and you got that whoopsidaisy lift and return?
Well a "thank-you-ma'am" is like that but not as severe.
I learned the term in the "old days" (1930s) when Dad piled us all in the car for The Sunday Drive.
Although I was taught thank-you-mum! Was told it came from the bobbing curtsy maids gave to employers in the *really old days of live-in household help; black, ankle length uniforms, white aprons and tiny white caps!
"Mum" being for employers; "ma'am" being reserved for The Queen.
Had not run into a thank-you-mum for years and years until, funnily enough, I was driving on a unimproved (dirt) road about a month ago and hit a thank-you-mum. I said the phrase aloud and then had to explain the meaning to my *young driving companion.
