www.alphadictionary.com

Has anyone had to gird oneself recently? I mentioned that I had to gird myself for retirement and was met with blank stares. I began to question my mental acuity, then I looked to an old friend:
Old English gyrdan "put a belt or girdle around; encircle; bind with flexible material; invest with attributes," from Proto-Germanic *gurdjan (cognates: Old Norse gyrða, Old Saxon gurdian, Old Frisian gerda, Dutch gorden, Old High German gurtan, German gürten), from PIE *ghr-dh-, suffixed form of root *gher- (1) "to grasp" (see yard (n.1)). Related: Girded; girding.
Throughout its whole history the English word is chiefly employed in rhetorical language, in many instances with more or less direct allusion to biblical passages. [OED]
As in to gird oneself "tighten the belt and tuck up loose garments to free the body in preparation for a task or journey."

I most often see this one in the phrase "to gird one's loins."

It is also the root of the steel beam used to reinforce parts of buildings.

Yes, loins are the only thing I have ever known to be girded. Used semi-ironically when preparing to take on an onerous or tricky task.