To Spread Out, To Extend, To Stretch
intransitive verb, godan verb
Remember 広い? Well this is like that, except a verb. When something does the action of getting wide, it means to spread out, to extend, or to stretch.
You already learned
ひろがる
The reading is the same as 広い, too, so as long as you knew that you knew this reading as well.
両足、もっと広がる?
Can you spread both of your legs more?
リビングルームは、この入り口から広がります。
The living room spreads from this entrance.
ウィルスは、すぐに全日本に広がった。
The virus quickly spread to all Japan.