Meaning of closely held

What do people mean by ‘closely held’ ? This is part of a question:

“Joe Dentice has an opportunity to buy 5% of Gold Star Oil, Inc., a closely held oil company. He wants to value the company so as to be able to make a decision on the fair price to pay for the investment.”

There’s a limited number of shareholders and shares may only trade on occasion, making pricing observability more difficult (as opposed to a very actively traded and quoted stock).