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OWL is a comprehensive writing resource covering topics from grammar to the writing process and citation in multiple popular styles. The link above directs users to the grammar section of the site. Navigate specific grammar topics from the left menu.
From the Purdue site: "The Online Writing Lab (OWL) at Purdue University houses writing resources and instructional material, and we provide these as a free service of the Writing Lab at Purdue. Students, members of the community, and users worldwide will find information to assist with many writing projects. Teachers and trainers may use this material for in-class and out-of-class instruction."
Available via ebrary, this dictionary series addresses specific usage of terms within disciplines, and within that context provides quick advice on grammar and usage. It, too, will require you to authenticate as a Suffolk user.
Another ebrary offering that provides online access to a reference guide that we also own in print form. This grammar resource has a bit more substance than the Hutchinson listed above. Authentication as a Suffolk user is required to access it.
"Strunk" is a well-loved classic of English usage. Because the Professor's 1918 edition of Elements of Style is now in the public domain, it is possible to find it free on the web. This online edition is supported by Project Gutenberg, and can be accessed in a variety of file formats. Another commonly cited version of the old Strunk is the one posted by Bartleby. Unfortunately, Bartleby usually comes with obnoxious pop-ups, so make sure your pop-up blocker is operational when you visit this site. Later editions of the print volume are called "Strunk & White," after E.B. White revised the original. These are not available free on the web. (But we do own them in paper format.)
While we have the useful Oxford English Dictionary and Oxford Reference Online Premium, we do not subscribe to the separate "Oxford Dictionaries." Still, this area providing tips on better writing is currently open access. Sections include Grammar, Spelling, Punctuation and more. There aren't a lot of entries in any category. Still, some of the tips cover classic writing conundrums like when you use I or me, or how to use the apostrophes in a proper way.
Jane Strauss is the author of a guide and workbook on English grammar. She now has a website companion, as well. Pick Grammar or Punctuation from the bright blue frame to the left. On the inner page, pick a more specific topic from the pop-open window of Table of Contents. A discussion with examples will be displayed. Exercises and quizzes are also offered.
Jack Lynch (also the author of a book entitled The English Language: A User's Guide), admits that he is "not a linguist, nor a scholar of the history of the language." He is, however, an English professor at Rutgers. So his dictionary-style usage guide can be a useful one.
Paul Brians, a professor of English at Washington State University created this page, which is an online companion to his book by the same title. There are individual links to specific topics related to common spelling gaffes and grammatical puzzlers. (Remember, the listing is usually listed under the error and not under the correct spelling or usage!) There are also links to "Supplementary Pages" and "Other Good Resources" at the bottom of the main page. A very handy display of tips for a quick check on a word or usage point!
The Chicago Manual of Style is the definitive source for scholarly style, from term papers to dissertations to book manuscripts. At this page, you can search the questions that have been sent to the editors. They cover anything from the proper use of abbreviations to the horrors of split infinitives. Use the search engine in the left frame to find Q&A entries that might apply to your question.
This extensive writing guide, written by Mary K. McCaskill of the Langley Research Center in Virginia is a NASA publication designed for technical writers. It is, however, a good basic guide that can benefit any writer who is a little shaky on the finer points of English grammar and punctuation. The file, which is 108 pages long, is in the form of a PDF.
This commercial site opts for a bright, hip design--and way too many advertisements and tangential links. Still, the readable style is useful for those who feel overwhelmed by grammar tips that are just TOO academic. Tips are organized in sections like Grammar, Punctuation and Style. And there's a list of "Top 5 Tips." The day I looked over this website, the number one tip was discussing the usage differences between affect and effect. (That's one that trips up a lot of people!)
This is a commercial website, so be prepared for pop-up ads and the like. Still, there are lots of postings on idiom/usage and grammar, articles on specific topics like writing letters and bibliographies and even quick quizzes to be found here. There is also a forum (you must register for--use an email address you don't mind being spammed) that provides lots of tips oriented towards second language English learners. Want more materials specifically for ESL? Take a look at our separate English as a Second Language Resource Guide.