玄, originally silk tie or knot for dyed silk, is pictographic character. 玄 serves as phonetic component to form characters. Characters formed by the phonetic component 玄 share compound vowels ian and uan.
Another version of the origin of 玄: red black.
In modern Chinese 玄 mainly express extended meanings: dark, incredible, profound, abstruse.
Characters formed by the phonetic component 玄
弦 蚿 舷 伭 娹 婱 妶 have the same pronunciation xián
炫 眩 铉 泫 怰 昡 袨 have the same pronunciation xuàn
玹 痃 have the same pronunciation xuán