A what? It is called a Frenulum.
It is the little piece of tissue that connects your lip to your gums (see below).
It is also the little piece of tissue that connects your tongue to the floor of your mouth (see below).
Why are these pictures important?
Because your dentist may tell you that your child, or you, needs a Frenectomy. That is where the doctor will cut the little piece of tissue in half. This is done in cases where the frenulum is getting in the way. Either it is in between the teeth causing a gap or in is tying the tongue to the floor of the mouth and thus hampering speech. It’s just good to educate yourself on what things are and why certain procedures are going to be done before actually getting them done.
And, there is always the option of piercing your frenulum.
But…. I’m not a big fan of that.