Basic Book Design/Widows And Orphans
Appearance
A widow is a short line (one or two words) ending a paragraph at the top of a page. Widows should be avoided.
An orphan is the first line of a paragraph ending a page.
Microsoft Word has automated widow/orphan control, in Format…Paragraph…Line and Page Breaks. I suggest not using it, for two reasons. First, Microsoft Word doesn't count the number of words in a widow. According to the Chicago Manual of Style (19.40), a ten-word line isn't a widow, and is acceptable.
Second, the Chicago Manual of Style doesn't say anything about orphans, so I presume these are acceptable. Orphans are always full lines (never one or two words).