The Gates arrest: What does "disorderly conduct" mean, exactly?

In Massachusetts and elsewhere, courts have said the “disorderly acts or language” must take place in public where others can be disturbed.

It is probably not a crime of disorderly conduct for a homeowner, standing in his own kitchen, to speak abusively to a police officer…

“I would say it is not constitutional to arrest someone in his home just for being loud and abusive to a police officer,” said Boston University law professor Tracey Maclin. “That’s why the cop asked him to come outside, where he could be arrested for being disorderly in public.”