Frequency: The word is one of the 3000 most common words in English.
1.
If you are talking about how great, important, or serious a difficulty or situation is, you can refer to the extent of it.
The government itself has little information on the extent of industrial pollution...
The full extent of the losses was disclosed yesterday.
N-SING: with supp, usu the N of n
2.
The extent of something is its length, area, or size.
Their commitment was only to maintain the extent of forests, not their biodiversity.
N-SING: with supp, usu the N of n
3.
You use expressions such as to a large extent, to some extent, or to a certain extent in order to indicate that something is partly true, but not entirely true.
It was and, to a large extent, still is a good show...
To some extent this was the truth...
PHRASE: PHR with cl [vagueness]
4.
You use expressions such as to what extent, to that extent, or to the extent that when you are discussing how true a statement is, or in what ways it is true.
It's still not clear to what extent this criticism is originating from within the ruling party...
To that extent they helped bring about their own destruction...
PHRASE [vagueness]
5.
You use expressions such as to the extent of, to the extent that, or to such an extent that in order to emphasize that a situation has reached a difficult, dangerous, or surprising stage.
He said he didn't like the president, but not to the extent of wanting to kill him...
PHRASE [emphasis]