From the USC Theses and Dissertation Formatting Guidebook

The things you learn each day...

"A widow occurs when the last line of a paragraph appears as the first line of a page. To
eliminate a widow, insert a page break a line earlier so that the last two lines of the
paragraph appear at the top of the next page.
An orphan occurs when a heading or the first line of a paragraph appears as the last line of a page. To eliminate an orphan, insert a page break before the orphan line."