好词典
hairline
UK //ˈheə.laɪn//US //ˈher.laɪn//
词源
复合词，源自 hair（头发） + line（线），14世纪后期首次记录，原指头发的轮廓线，后引申为任何细线状事物。
noun
❶ 指发际线，即头发与额头交界处的轮廓线，常用于描述发型或脱发情况。
“Her hairline is naturally high, giving her a broad forehead.”
（她的发际线天生较高，显得额头很宽。）
“Stress caused his hairline to recede over the years.”
（压力导致他的发际线这些年逐渐后移。）
❶ 形容极其细微的裂缝或分界线，常用于描述瓷器、玻璃或岩石的细小裂痕。
“The antique vase had a hairline crack that was barely visible.”
（古董花瓶上有一道几乎看不见的细微裂纹。）
“Engineers detected hairline fractures in the bridge's support beams.”
（工程师在桥梁支撑梁上检测到细微裂缝。）
同义词:hair border, fracture line, fine crack
常见短语
hairline fracture — 指骨骼或材料上极细的裂缝，通常需要X光才能发现，形容损伤轻微但存在。
“The X-ray revealed a hairline fracture in his wrist bone.”
（X光显示他的腕骨有一处骨裂。）
receding hairline — 描述发际线逐渐后退的现象，常见于男性脱发的早期阶段。
“He started using special shampoo to slow his receding hairline.”
（他开始用特殊洗发水延缓发际线后退。）