Q. I've just bought a series of books for my 5-year-old son. One story includes the line "bad guys chased after some good guys." Here's my question: is it correct to write "chased after" in this sentence? I thought that chase is a transitive verb that takes an object and no preposition is needed.

A. Chase is both a transitive and intransitive verb, and both uses date back to the 14th century. The construction chase after does have more informal use, but it is also acceptable in everyday or formal prose. One example that comes to mind is chase used to mean "to follow with the intention of attracting or alluring," as in "He is always chasing after women half his age." After is usually used in this informal intransitive sentence, although it may be omitted (making the sentence transitive).

Here are some examples of chase after used in edited prose whose contexts are standard:

"When a researcher's personal life becomes the object of intense scrutiny, s/he becomes the butterfly that has been exoticized and chased after." (Ellen Cushman, College English, September 2001)

"Franzen's wavering between the aesthetic and the social recalls the uncertainty of his Harper's essay, and is the more peculiar because he seems, at other moments, perfectly capable of trusting the bona fides of the implicit, perfectly capable of respecting the intrinsic and not chasing after the explicit." (James Wood, "Abhorring a Vacuum," The New Republic, October 18, 2001)

"Others worry that by cherry-picking the most desirable patients, hospitals will ignore less profitable cases. After all, they note, no one seems to be chasing after terminal cancer patients on Medicaid who can wind up costing hospitals much more than the reimbursement they receive." (Anita Sharpe, The Wall Street Journal, May 1, 1997)

Q. I know these words are rarely used today, but I've come across the words castled and castellated. I had thought that the first would refer to a move in chess and the latter to the architecture of a building that is similar to a castle. Could you clarify this?

A. You're pretty much on target. The verb castellate shows two sense definitions in the Unabridged:

transitive verb : to build like a castle : build or furnish with battlements
intransitive verb : to take the form of a castle <castellating clouds>

The participle castellated, when used as an adjective, would in most cases refer to the first sense to describe structures built to resemble castles (as in "a castellated mansion").

The verb castle can refer to the chess maneuver, or it can mean "to establish in a secure position." This verb tends to be used figuratively – a man can be "castled up in his cabin in the woods," for example. There is also an obsolete sense of the verb meaning "to enclose (as a water conduit) in stone walls."