forehead; brow
「額」 has another reading with different meanings.
(picture) frame; framed picture
彼女の額には汗がにじんでいた。
Sweat was beading on her forehead.
暑くて額に汗が流れてきてしまった。
It's hot and sweat started running down my forehead.
彼女は額に手を当てて考え込んでいた。
She was thinking deeply with her hand on her forehead.