You should, of course, own a good college dictionary. In it you will surely find a table of proofreader's signs and symbols. Consult it — I often use these conventional markings.
Acc = Accuracy! Your quotation is inaccurate in some detail, perhaps by omitting an initial capital letter at the start of a line. If your quotation is run into your own text (as opposed to being indented and typed line for line), indicate line breaks by using a slash.
Agr = Agreement: the subject and verb are not in agreement as to number. Plural subjects take plural verbs. The mere presence of a plural noun in between the subject and verb does not justify changing the verb to the plural if the grammatical subject is singular. Watch out for constructions like "Shakespeare's use of imagery and connotation adds to the powerful effect of his characters' speeches." The grammatical subject there is "use"; the fact that two other nouns intervene doesn't change this; the verb must be singular.
CF = Comma fault: you are using a comma here to separate independent clauses or sentences. Substitute either a semicolon, if the items are closely related, or a period.
Dict = use your dictionary: look up the word and figure out what's wrong with the way you used it.
Frg = Fragment: this is not a sentence, because it lacks a subject and/or a predicate. (Look these terms up in your dictionary if they seem obscure.) However, if you've earned your reader's confidence, an occasional fragment used for rhetorical effect will be acceptable.
Huh? = An expression of your reader's befuddlement or incredulity. See "Obsc" below.
Obsc = A more polite equivalent of "Huh?" Your meaning is unintelligible. (The fact that your instructor may be perfectly well able to guess at what you meant to say doesn't matter here. It's your job to actually say what you mean.
Poss = a more long-winded way of drawing your attention to misuse (or absence) of the apostrophe in a word in the posessive case
R = Rewrite the paper.
S or SP = spelling error (often involving the misuse of the apostrophe). Favorite horrible examples result from confusion between "its" and it's" and between "to" and "too." Errors like this are generally taken by educated readers as signs of semi-literacy. That sounds harsh, but it's true.
W = wrong word, fault of diction.
# = the "space" mark (called the pound mark on the telephone keypad) as used by proofreaders. Leave a space where this mark is inserted. You'll find it if you write "for awhile" instead of "for a while" or "eventhough" instead of "even though".
¶ = the "paragraph" mark. Probably means "Begin a new paragraph here" but may also mean "You call this a paragraph?"
= the "dele" or delete symbol.
Updated April 29, 1996 & again, February 18, 1999.