London ? It weighs in at more than 130 pounds, but the authoritative guide to the English language, the Oxford English Dictionary, may eventually slim down to nothing.

Oxford University Press, the publisher, said Sunday so many people prefer to look up words using its online product that it’s uncertain whether the dictionary’s next edition will be printed on paper at all.

The digital version of the Oxford English Dictionary now gets 2 million hits a month from subscribers, who pay $295 a year for the service in the U.S. In contrast, the current printed edition — a 20-volume, 750-pound ($1,165) set published in 1989 — has sold about 30,000 sets in total.

It’s just one more sign that the speed and ease of using Internet reference sites — and their ability to be quickly updated — are phasing out printed reference books. Google and Wikipedia are much more popular research tools than the Encyclopaedia Britannica, and dozens of free online dictionaries offer word meanings at the click of a mouse. Dictionary.com even offers a free iPhone application.

By the time the lexicographers behind the century-old Oxford English Dictionary finish revising and updating its third edition — a gargantuan task that will take a decade or more — publishers doubt there will be a market for the printed form.