I’ve posted about errors in signs declaring business hours before. A giant European home furnishings company you may have heard of is among the businesses that have gotten it wrong.
Why should the phrase be “open daily” and not “opens daily”? Because one is idiomatic and one isn’t; or if you prefer, “open daily” has been idiomatic longer, since the sign is, itself, evidence that “opens daily” has become idiomatic in Singlish.
The best I can do for a usage citation is a couple of dictionary entries for “daily”, which give “open daily” as an example, suggesting that this is the most natural and intuitive phrase, as far as dictionary writers are concerned.
Then there’s the fact that the phrase “opens daily” gets Google 253,000 hits whereas “open daily” gets 10,800,000. The images for “opens daily”, in comparison to the images for “open daily”, are telling, too.
Leaving aside calls to authority and statistics, the syntactic difference is interesting. “Open daily” uses “open” as an adjective, and “opens daily” uses “open” as a verb. We want to know when the business is open. We do not care when the door of the business is opened by some employee with a key. The emphasis is misplaced.
There is a further confusion lurking under the surface, which is that when we do use “open” as a verb for a business, we sometimes mean it in the sense of “to launch” or “to open for the first time”. So the phrase “opens daily” makes it sound like maybe the business is having a grand opening every day, which is ridiculous. Grand openings are not everyday occurrences.
You can use “open” as a verb if you really want, especially in a sentence rather than as a notice on a sign. But I think the verb needs a strong contextual justification.
Opens at 9:00 a.m.
Closes at 5:00 p.m. Monday to Thursday
Closes at 3:00 p.m. on Friday
The Ikea sign is particularly bad because of the colon.
Opens Daily: 10am to 11pm
The text suggests that the door is opening (and closing) continuously from ten in the morning to eleven at night! Why? Because there are two adverbs modifying the verb “opens”: the word “[once] daily” and the phrase “[from] 10am to 11pm”. The first can legitimately indicate when the business opens; but the second is meant to say when the business is open.
This is what I think the sign should say:
10 a.m. to 11 p.m.