This stems from a discussion over on ELL which has moved beyond being useful to second-language learners. In short, consider the sentence:

I weigh about 5 pounds.

What part of speech is "about?"

Since the verb "weigh" is not having any effect on the "about five pounds," I think it must be intransitive. That leaves the "about five pounds" as a long adverbial phrase, modifying the verb, right?

If that is correct, then isn't "about" an adverb modifying the adverbial noun "pounds?"

Would the answer hold true if we were talking about the price tag on something?:

This shirt costs about 5 pounds.

This stems from a discussion over on ELL which has moved beyond being useful to second-language learners. In short, consider the sentence:

It weighs about 5 pounds.

What part of speech is "about?"

Since the verb "weigh" is not having any effect on the "about five pounds," I think it must be intransitive. That leaves the "about five pounds" as a long adverbial phrase, modifying the verb, right?

If that is correct, then isn't "about" an adverb modifying the adverbial noun "pounds?"

Would the answer hold true if we were talking about the price tag on something?:

This shirt costs about 5 pounds.