素 sù plain

plain; vegetarian; element

怎么记住“素”: 龶 plant + 糸 thread = plain. The bride wants no lace, just a small plant stitched in white thread on a dress that is simple and plain.

部件结构

素 = 龶 plant + 糸 thread

Gushi 故事

The bride wants no lace, just a small plant stitched in white thread on a dress that is simple and plain.

Bound morpheme with a wide range: "plain, undecorated", "vegetarian", and "element/factor" in compounds.
吃素 (chī sù) "to eat vegetarian" is a common verb-object phrase; 素质 (sùzhì) "(inner) quality, character" is everywhere in education and self-improvement talk (提高素质 "raise one's overall quality").
因素 (yīnsù) "factor" and 元素 (yuánsù) "element" are the standard abstract/scientific terms.
As a suffix it marks biological/chemical substances borrowed or coined in modern science: 维生素 (wéishēngsù) "vitamin", 激素 (jīsù) "hormone", 抗生素 (kàngshēngsù) "antibiotic".