- is usually a phrase whose meaning is not obvious
- gets the meaning accepted due to usage over time
- is a linguistic device
Advanced dictionaries may list idioms and their usage.
During my middle school days, one of my uncles gave me books (including “A Book of Idioms”) .
From the book, I learned that “the hand that rocks the cradle” stands for “a mother”.
“Rain cats and dogs” is an idiom which means “Rain heavily”.
In this example, the idiom uses a metaphor.
No one knows the root of the idiom “kick the bucket” meaning “dies”. Someone guessed that a man being hanged by a rope might kick a bucket.
Idioms should be used sparingly.
If you combine two idioms mentioned above and say “The hand that rocked the cradle kicked the bucket” you might receive LOL (Laughing Out Loud) for the illogical construct.
U Khin Maung Zaw (KMZ, EC76) added :
Believe it or not, this subject is one of the many we learned from U Hla Min (KJ to some of us) while we were at the UCC. As some of us were preparing for TOEFL, KJ prepared us by teaching the ins and outs of the language.
Some of these idioms are regional in nature, after some time living here, I tend to use many idioms as they come naturally. Well, that’s until a childhood friend of mine kindly reminded me that many of them were having hard time fully understanding what I meant in the posts.
As of now, I am trying my best to use US idioms as little as possible, at times I feel like I have to write more as if I could not communicate to get my point across. I did it again, bad of me.
“to get my point across” is an idiom meaning “to make people understand what one is saying” (per Merriam Webster).