What is an idiom?

An idiom is a combination of words that has a meaning that is different from the meanings of the individual words themselves. It can have a literal meaning in one situation and a different idiomatic meaning in another situation. It is a phrase which does not always follow the normal rules of meaning and grammar.

To sit on the fence can literally mean that one is sitting on a fence. 

I sat on the fence and watched the game. 

However, the idiomatic meaning of to sit on the fence is to not clearly choose a side regarding some issue. 

The politician sat on the fence and would not clearly state his opinion about the tax issue. 

Many English idioms are similar to expressions in other languages and can be easy for a learner to understand. Other idioms come from older phrases which have changed over time.

To hold one's horses means to stop and wait patiently for someone or something. It comes from a time when people rode horses and would have to hold their horses while waiting for someone or something.

"Hold your horses," the man said when his friend started to leave the store. 

Other idioms come from such things as sports and may require some special cultural knowledge to understand them.

To cover all of one's bases means to thoroughly prepare for or deal with a situation. It comes from the American game of baseball where you must cover or protect the bases. 

I tried to cover all of my bases as I prepared for the job interview. 

Structure of Idioms

Most idioms are fixed in their grammatical structure. The expression to sit on the fence cannot become to sit on a fence or to sit on the fences. 

Other idioms are the result of a change in grammatical structure and would generally be considered to be incorrect.

To be broken literally means that something is broken. 

The lamp is broken so I cannot read my book.

To be broke is grammatically incorrect but it has the idiomatic meaning of to have no money. 

I am broke and I cannot go to a movie tonight. 

There can also be changes in nouns, pronouns or in the verb tenses. 

I sat on the fence and did not give my opinion. 

Many people are sitting on the fence and have not made a decision. 

Adjectives and adverbs can also be added to an idiomatic phrase. 

The politician has been sitting squarely in the middle of the fence since the election. 

That is why it is sometimes difficult to isolate the actual idiomatic expression and then find it in a dictionary of idioms. 

What is a phrasal verb?

A phrasal verb is a two-part or three-part verb and is sometimes called a compound verb. It is a combination of a verb and an adverb, a verb and a preposition, and a verb with an adverb and a preposition. It can have a literal meaning that is easy to understand because the meaning is clear from the words that are used. It can also have an idiomatic meaning which cannot easily be understood by looking at the words themselves. 

Verb and Adverb (run + around)

to run around (something) - to run in a circle around something (literal meaning) 

The dog ran around the tree. 

to run around (somewhere) - to go to various places to do something (idiomatic meaning) 

I spent the day running around downtown. 

Verb and Preposition (run + into)

to run into (someone or something) - to hit or crash into someone or something (literal meaning) 

The car ran into the truck on the busy street. 

to run into (someone) - to meet someone by chance (idiomatic meaning) 

I ran into my friend in a restaurant yesterday. 

Verb and Adverb and Preposition (run + around + with)

to run around with (someone) - to be friends and do things with someone or with a group of people (idiomatic meaning) 

The boy is running around with a bad group of people. 

Some idiomatic expressions are made with a phrasal verb plus some other words. These words are used in a fixed order to give an idiomatic meaning. 

to run (verb) around (adverb) like a chicken with its head cut off - to run around with no purpose 

I ran around like a chicken with its head cut off as I prepared for my holidays. 

What is a proverb?

A proverb is a short saying or sentence that is generally known by many people. The saying usually contains words of wisdom, truth or morality that are based on common sense or practical experience. It is often a description of a basic rule of conduct that all people generally follow or should follow. Proverbs can be found in all languages.

money doesn't grow on trees - money is not easy to get and you must work hard for it 

The girl's father says that money doesn't grow on trees when the girl asks him for money. 

the early bird catches the worm - arriving early gives one an advantage 

My boss always comes to work early because he believes that the early bird catches the worm. 

the pen is mightier than the sword - writing and ideas are more powerful than the use of force 

The pen is mightier than the sword and a good idea will defeat the strongest army.