carriage bolt 

(noun, USA/SAE Standard) A bolt having a round head with a square, ribbed, or fluted boss underneath it. The function of the boss being to bite into timber to prevent the bolt turning while the nut is being tightened.

This term is often, and wrongly, considered interchangeable with "coach bolt", which is UK/Australian slang for a lag bolt. This may seem a trivial inconsistency to the layman, but is a mixup which has cost innumerable companies lots of money and confused a huge number of people.
One may perform a quick test to determine whether an item is a carriage bolt or lag bolt/lag screw: Is it driven (tightened) by its head or can only nuts be driven up it? If the former, it's a carriage bolt, if the latter, it's <i>probably</i> a lag bolt.

Origin: Old French <i>cariage</i>, from <i>carier</i> &#8216;carry&#8217;; bolt (unchanged), Old English. There is no reliable information as to whether the carriage bolt got its descriptor through the manufacture of carriages/coaches or whether 'carriage' refers to the fact that such a bolt is a load-bearing item.

Goddamn, I hate these translated instruction manuals. This thing just tried to tell me to use a screwdriver to tighten a carriage bolt!

carriage bolt by Ike January 26, 2005

under carriage 

another name for a womans ass

"damn you saw the under carriage on that chick??"

under carriage by doog-larry April 20, 2006

Cozy Carriage

An action in which one puts of all a male’s testicles in a different individuals mouth and falls asleep in that position.

Thanks for the Cozy Carriage last night bro! Felt very comfortable

Cozy Carriage by jizz12345 December 7, 2022

under carriage flow

When the breeze passes through the loins

Denise stood up over the floor register to get some UCF (under carriage flow)

under carriage flow by Sharon Thunderbush October 27, 2023

Carriaged 

Impregnated; knocked up, made to be with child.

mc chris: She disrobed her party clothes and then said I'm sorry love, I'm embarrassed she got carriaged while in Paris from some thug.

Carriaged by whynotbeme2 September 24, 2010

Carriage-Cruiser 

In my small town of 300 people we have a group of new mothers who push their baby carriages around the town for exercise. Our town now call them the Carriage-Cruisers

There goes the new town carriage-cruisers down the road pushing their babies in strollers.

Carriage-Cruiser by KRYSANN October 18, 2006

Peasant Carriage 

Most means of public transportation
IE: Bus, Train, Coach etc.

Me "Why not just get a bus and save money"
Mark "I must contest, I refuse to travel on the peasant carriage"
Me: "Thou must protest as your financial situation is dyer"
Mark "Once yonder giro is cashed ones means of transportation would become more favourable kind sir"

Peasant Carriage by Syharrisonb July 16, 2011