noun
A brush used for painting pictures, typically with watercolors or oils.
彼女は絵筆を手に取り、キャンバスに向かった。
She picked up a paintbrush and faced the canvas.
筆 is a general brush for writing or painting, while 絵筆 specifically refers to a brush for painting pictures.
Compound of 絵 (e, 'picture') and 筆 (fude, 'brush'). The reading えふで is a straightforward combination.