As I have always heard, it is a Poker reference to being able to pat the table when you have a good hand and do not need to be dealt any more cards.
Excerpt from the a website explaining this possible origin:
Every poker player knows that feeling when one is dealt a pat hand: you glance at the 5 diamonds you've been dealt, and it makes a vivid impression. You don't need to glance at it again and again to verify what you have: you have it down pat..
Although I buy the idiom's origin being the poker reference, another explanation I've read is that a pat (in the sense of being exact, appropriate) comes from "hit with a pat", to hit accurately, not miss.
If you have something down pat, you understand it totally. This phrase can be used when you have learned a new skill, or memorized something. You say "I have that down pat," when you are confident that you know it.
Plenty more down cellar in a teacup
This phrase originates with the 'Old Bailey' in London, where the remand cells were literally under the court itself.
There is no such phrase. There is a word rampage. It is of Scottish origin, perhaps from RAMP, to rear up.
The correct way to write this is pat down. So your answer is two words.An example sentence is: This officer will give you a pat down to see if you have drugs on you.
IRISH
If you have something down pat, you understand it totally. This phrase can be used when you have learned a new skill, or memorized something. You say "I have that down pat," when you are confident that you know it.
ponerse el cinturon
Plenty more down cellar in a teacup
This phrase originates with the 'Old Bailey' in London, where the remand cells were literally under the court itself.
This phrase originated in a popular song of the 1880s, "Is That Mr. Reilly?" by Pat Rooney, which described what its hero would do if he suddenly came into a fortune.
There is no such phrase as "eat you".
Down-and-out is from a situation where a beaten prizefighter is knocked unconcious. It originated in 1889 in American English from pugilism (boxing or fist fighting).
There is no such phrase. There is a word rampage. It is of Scottish origin, perhaps from RAMP, to rear up.
The phrase of Greek origin referring to the common people is "hoi polloi."
The correct way to write this is pat down. So your answer is two words.An example sentence is: This officer will give you a pat down to see if you have drugs on you.
"on the rocks"