From: utzoo!decvax!genradbo!grkermit!chris Newsgroups: net.nlang Title: Re: Using data as a singular noun Article-I.D.: grkermit.301 Posted: Fri Feb 25 15:33:14 1983 Received: Sat Feb 26 03:31:12 1983 References: floyd.1217 The term you want to use instead of "mass noun" is "non-count noun." The opposite is obviously "count noun." This is a reasonably well established concept. (I learned it in the fifth grade or so.) The term is used to distinguish between nouns for which the plural form indicates a discrete number of the item, and those for which the plural indicates an undistinguished jumble of the item. Other non-count nouns are "water", "sugar", and "mail." I think that "data" and "datums", (considered an acceptable plural form by most dictionaries) should be treated as non-count nouns, and so your usage was correct.