Green’s Dictionary of Slang

a non-sexual relationship between males.

2007		(ref. to 1990s) age.com.au 🌐 The term was coined in the late 1990s by Dave Carnie, editor of Big Brother, an American skateboarding magazine. [...] bromance specifically described the relationship between skate-buddies who spent lots of time together and/or shared hotel rooms on road trips.
2014		C. Eble UNC-CH Campus Sl. Spring 2014.
2020		D. Winslow ‘Crime 101’ in Broken 65: [They] bust his chops for having a ‘man crush,’ a ‘bromance’ with Robie.