PORTLAND – The University of Southern Maine has received a $2.2 million gift to benefit a lifelong learning program open to students over the age of 55.

The gift from the San Francisco-based Bernard Osher Foundation is USM’s largest cash donation ever.

“We are absolutely thrilled,” USM’s president, Richard Pattenaude, said Tuesday. “It reaffirms our work and provides an opportunity to create one of the finest lifelong learning programs in the United States.”

The university’s Senior College, launched in 1997, will be renamed the Osher Lifelong Learning Institute in honor of the donor.

The program was the brainchild of Rabbi Harry Sky of Portland, who taught the first class, on spirituality. Since then, more than 2,000 people have participated. Similar programs have been set up in Maine, including one on Mount Desert Island.

The program offers classes on various topics, but no exams. Faculty members, many of them retired college professors, donate their time, said Kali Lightfoot, the program’s director.

Last year, state legislators allocated $150,000 to bring the program to other areas in the state.

The foundation’s gift provides a $2 million endowment, another $150,000 to help retrofit classrooms to better accommodate older people and another $50,000 to help solve transportation problems. The money also will fund a researcher.

Sky said the grant from the Osher foundation is important for reasons beyond the endowment, which will ensure its future.