noun which may take the genitive case particle 'no', na-adjective, noun
Describes objects that are notably wide, such as belts, ribbons, shoes, or brims. Often used attributively with の or as a na-adjective.
幅広のベルトが流行っている。
Wide belts are in fashion.
この靴は幅広なので、足が楽だ。
These shoes are wide, so they're comfortable.
広い is the general i-adjective for 'wide' or 'spacious' and can describe spaces, areas, or abstract breadth. 幅広 specifically refers to the width of objects and is often used in compound-like attributive forms.
Compound of 幅 (はば, 'width') and 広 (ひろ > びろ, 'wide'). The reading びろ is a rendaku form of ひろ.