Floss is how you clean the one place a toothbrush cannot fully reach: right where two teeth touch.

In kid words

"Floss is the thin string we slide gently between your teeth, right where two teeth touch, to clean the spot your toothbrush can't reach." It only takes a minute, sliding up and down the side of each tooth. Plenty of kids need a grown-up's hands to help for a while, and that's completely normal.

The parent version

Floss is a thin thread, or a small pick that holds one, used to clean between two teeth, the tight contact area a toothbrush bristle cannot fully reach on its own. Mainstream guidance, including from the American Academy of Pediatric Dentistry, generally ties the starting point to contact rather than to a birthday: once two teeth are touching each other, whether that's a pair of back baby molars or the first grown-up teeth arriving years later, the snug space between them is worth cleaning daily.

Until then, a gap that is still open between two teeth is usually a space a toothbrush can reach well enough on its own. Coordination is the other piece of this: flossing asks more of small hands than brushing does, so plenty of children need a parent to do it for them well past the age they brush solo. There is no single switch-over moment that fits every child, so ask your pediatric dentist what makes sense for your child's own teeth and timeline.

Where you might hear it at our office

Flossing has a standing spot in every routine cleaning and exam here, right after the polish, wherever a child's teeth are touching closely enough to need it. It's one more pass your child doesn't have to think about, since the hygienist handles it that visit no matter how flossing has gone at home lately.

The name turns up around our Naples office too, home to the S.S. Flossy pirate nook, and to a picture book by the same name waiting at the Storybook Reef. If another word from a visit is still a mystery, the rest of the dictionary is right here.

Related words

Words that often come up alongside floss: plaque, calculus, cleaning.