Most commonly seen in 生肖 (Chinese zodiac) and 肖像 (portrait). As a surname, 肖 is a simplified variant of 萧 — many people surnamed 萧 were reassigned to 肖 during simplification.
mistakes
As a surname it's pronounced Xiào (4th tone), but many people say Xiāo (1st tone) because of the connection to 萧. Both are heard in practice.
Bottom flesh radical (the radical form of 肉, visually identical to 月 moon but distinct in meaning) — anchors 肖 to the body/anatomy family alongside 胃 stomach, 肝 liver, 胆 gallbladder. Here it stands for 'the flesh of a child' born from the parent.
Top three-stroke small-variant of 小 sits above the flesh radical, giving the picture of 'a small piece of flesh' — a child resembling a parent in miniature form. From this came the verb sense 'to resemble' and the noun sense 'likeness, portrait.' The same top appears in 当, 尚, 党.