When you italicize your writing, you print or type in the slanted letters called "italics." You can italicize a word in a sentence when you want to emphasize it.
People italicize for various reasons: they might italicize the title of a book, or a section of dialogue that's yelled by a character in a story. Print that you italicize usually slopes from left to right, and it resembles script or cursive writing. Italicize and italics come from the Latin word for "Italian,"italicus. This print style was named in honor of the Italian printer credited as the first to use it.