What do brackets mean in a sentence?

I usually do okay with most grammar rules. I do suffer some confusion over the use of apostrophes time to time. However I do not ever recall being taught why brackets are used within a sentence. There is currently a pit thread named I [object to] Pit Rule #5 (I am not linking to the thread because it is not relevant to my question), I do not understand why object to was placed in brackets. Can someone please explain?
[sub]Now that I have stated I do alright (or is it all right?) on my grammar,I will be nitpicked on my grammar usage[/sub]

Brackets usually indicate editor-added wording. In the specific case you mention, I believe a mod edited the title for clarity and added the words in brackets.

Correct, and very popular in newspapers where someone is being quoted but additional information is required in the quote to enable the reader to make sense of it all.

The original quote might look something like this: “We needed to come out strong in the first period against them and we did, but that penalty really cost us.”

The revised edition might be: “We needed to come out strong in the first period against (Ottawa) and we did, but that penalty (to Maloney) really cost us.”

ETA: Also brackets can be used to separate a clause within a sentence. “I really liked the dress she was wearing (the blue colour reflected her eyes) but it was not appropriate for the occasion.”

Etc. Yadayadayada

All right.

Leaffan: I think you’re confusing brackets with parentheses.

Yep. Leaffan and others: parentheses mask an independent but related thought, while brackets indicate that a change has been made.

Brackets imply that the tone and intent of the message are unchanged, so “I’d be happy to sell this Archimedes screw pump to you” could be edited to “I’d be happy to sell [you] this […] pump” but not “I’d be happy to […] screw […] you” (even if she was implying that she would!) and certainly not “Screw […] you!” Hope that’s clearer.

Hmmm… A rose by any other name… They look the same in printed text to me and I certainly was never taught any difference. I accept your correction though.

Brackets in quotes, as alluded to above, usually mean information supplied by the editor or quoter *(or in the OP’s example by the moderator acting as editor), for clarity. Suppose, for example, you want to quote a specific sentence – but it begins with “He” or “It” – the antecedent that the pronoun refers to having been idientified two sentences previously. You’re entitled to emend the quote to read “[Churchill] was also a master of periodic prose,” or “[The long-snouted echidna] is native to New Guinea” where the original had “He was also a master…” or “It is native to…”

The other common use for brackets is in tiered parentheses, where one parenthetic statement lies inside another. [I can’t think of a good example (other than this one).]

They look the same? The brackets are square and the parentheses are round. It’s a fairly important distinction because parentheses are normally part of the original material while brackets are editorial.

sic is usually in parentheses, right? sic = “as I found it,” according to an English teacher I had. It’s used to indicate the original quote is incorrect, but that’s the exact quote.

“Ammericans (sic) sure are dumb,” he wrote.
The word is spelled incorrectly, and the editor doesn’t want his own ability questioned for it. He wants you to know he didn’t make the mistake but is reproducing the printed word faithfully.

“One of the boys are (sic) missing,” police said.
The verb should be “is.”

Other than that, I thought brackets offset what the editor was adding/changing slightly vs. what the original author might have put in parentheses. It occurs to me that if you’re quoting someone (e.g. words coming out of his mouth at a press conference), you aren’t contending with the possibility of parentheses from the original source.

To those commenting upon Leaffan’s use of parentheses: in his defense, it is not at all uncommon for newspapers to use parentheses where they should use brackets. I sometimes wonder if they don’t have brackets available in their fonts.

It also just occurred to me that the rules I’m using are how it’s done in US English, but that print sources from other English-speaking countries have different quotation marks, and might also have different parentheses or brackets. Leaffan is in Canada… any Ontarians want to chime in?

I’ve only ever seen “sic” in square brackets.

I wouldn’t say “only”, but that’s by far the commonest, and it makes sense, because “sic” is an addition to quoted text.

Ditto. I don’t specifically recall seeing in in parentheses, but it wouldn’t surprised me. However, brackets are what I usually see.

FWIW, the round ones are commonly called “brackets” in the UK. I had never heard the word “parentheses” before I moved here, although IIRC “parenthetical [reference]” is commonly used.

Sic is Latin for thus; in English idiom it means “hey, it was already like this”.

I knew how to use sic in a sentence. I appreciate all the replies. I often use parentheses, so those were not much of an issue either. I kept seeing brackets mostly used in quotes on newscasts, and until today I had no idea why. Those bracketed words looked like they belonged in the sentence. It all makes sense now. I wish I knew this fact when I was doing writing for college, it would have made quoting sources so much easier.

If you’re going to be pedantic enough to use [sic] then you need to be pedantic enough to always italicize the sic part: [sic]. Sic is still considered to be a Latin drop-in into English and so requires the italics. Similar to ibid. or et al.

I’ve never liked that idea. If it’s in common usage, it shouldn’t need to be italicized. Schadenfreude is the default English term for schadenfreude; why should it be italicized?

We don’t italicize tandoori or wigwam or kamikaze or hoi polloi…