A gel is an apparently solid, jellylike material formed from a colloidal solution. By weight, gels are mostly liquid, yet they behave like solids. An example is gelatin.
In fiber-optic communications, a gel resembling petroleum jelly[?] in viscosity is used to surround a fiber, or multiple fibers, enclosed in a loose buffer tube. This gel serves to lubricate and support the fibers in the buffer tube. It also prevents water intrusion if the buffer tube is breached. Gels are also used in fiber-optics as index-matching materials.
... tube that connects the urinary bladder to the outside of the body. The urethra has an excretory function in both sexes, to pass urine to the outside, and also a reproductive ...