A rash guard is a type of tight-fitting shirt that people wear while doing water sports or other activities that involve being in the water. It helps protect the skin from rashes and sunburn. Full definition
I like for my twins to wear long sleeve rash guard tops for added sun protection. (twiniversity.com)
There are even matching rash guard tops, too! (redbookmag.com)
We've used rash guard shirts on our kids for years and they're so much easier to deal with rather than constantly applying sunscreen. (thebarefootnomad.com)