When two people of different age do everything together and hang out with the same crowd and don't find anything weird about it. The 2 usually look very alike and are hard to tell apart.
"I always see those 2 together, its like they're twins"
" I know, and ones 3 years older than the other... They're such Danahy Brothers!"
" I know, and ones 3 years older than the other... They're such Danahy Brothers!"
by Flordiagrl85 July 13, 2009
Get the Danahy Brothers mug.