"If you’re familiar with HTML, this won’t be a complete departure (though there are no closing tags). .TH is the tag for titles, while .SH is for section header

"If you’re familiar with HTML, this won’t be a complete departure (though there are no closing tags). .TH is the tag for titles, while .SH is for section header. You can format text to be bold or italic with .B or .I, respectively." I love this retrospective explanation of nroff in terms of HTML.