Corp Governance: What does "meet regularly" mean?

In the example #19, page 249 The vignette states: “at her first board meeting, the company’s first in six months.” Q 19 says That this is a responsibility (to meet regularly) the board failed to meet. So, what defines “regularly?”

Quarterly or monthly seems to be the rule of thumb.

I would say quarterly is enough- anything longer than that is probably too infrequent.

thanks