What's the difference in "()" and "[ ]"?

Although () are commonly known as brackets or round brackets, they are properly known as parentheses. [] are brackets or square brackets. In formal essays, parentheses are used to enclose a thought that is somewhat tangential to the main idea of the sentence. Square brackets are used to enclose a word or words that are not properly part of a quote but are inserted to make the quote more intelligible or grammatically correct.

depends where you are and in what context really ... () usually contain amplification statements that better explain something that you've just written (i.e. a smart word use or something), while [ ] are used often to list alternatives [words, phrases, clauses] like a list where you can choose .... sometimes they are used together as nested brackets too...

in the pance where i work we use the following as a Europena standard:

BRACKETS

2.20 Round brackets. Also known as parentheses, round brackets are used much like

commas in 2.13 above, except that the text they contain has a lower emphasis.

They are often used to expand on or explain the preceding item in the text:

ARZOD (an employment service) is based in Ruritania.

2.21 Round brackets in citations. Use a pair of round brackets when citing

numbered paragraphs from legal instruments, and close up to the article

number:

Article 3(1), Article 3(1)(a), Article 3a(1), etc.

2.22 Bracketed sentences. A whole sentence in brackets should have the final stop

inside the closing bracket. Do not forget the stop at the end of the preceding

sentence as well.

2.23 Square brackets. Square brackets are used to make insertions in quoted

material. They are also used by convention in administrative drafting to

indicate optional passages or those still open to discussion, so do not replace

with round brackets.

When translating, also use square brackets to insert translations or explanations

after names or titles left in the original language.

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hope that helps

From what I know [ ] is usually used in interveiws when the person being interveiwed doesn't say the word but they mean that.

Example- famous celebrity: I have two [children]

And these ( ) mean something you think

Example: I am 13. (14 in September.)

() u no wut they r used 4 and [] go inside () ex: They were here (the horse[and the dog] were there) sorry not gud ex but u get the pointt

() are parentheeses

[] are brakets

[] is prettier than ()