gel

1 . A substance, resembling petroleum jelly in viscosity, that surrounds a fiber, or multiple fibers, enclosed in a loose buffer tube. Note: This gel serves to lubricate and support the fibers in the buffer tube. It also prevents water intrusion in the event the buffer tube is breached. [FAA] 2 . Index-matching material in the form of a gel. [FAA] Synonym index-matching gel. See index-matching material.