Definition of Brony in US English:

Brony

noun

US
informal
  • A man who is a fan of the My Little Pony television program and range of toys.

    ‘he's seen his band of Bronies grow from a few hundred members to thousands’
    as modifier ‘the Brony community’

Origin

Early 21st century: blend of bro and pony.

Pronunciation

Brony

/ˈbrōnē//ˈbroʊni/