Zhè zhāng tú shì shǐliàngtú, fàngdà bú huì shīzhēn.
This image is a vector graphic — zooming in won't distort it.
Tips
memory
矢 originally means 'arrow' — and an arrow has both a length (magnitude) and a direction it points. So 矢量 = 'arrow quantity' = a vector. The contrasting 标量 (scalar) uses 标 (mark/measure) — just a number, no direction.
usage
Technical/scientific term. In math classes, physics, and graphics software (矢量图 vector graphic) you'll see this; in everyday speech people don't say it.