Invisible Fluorescent Ink隐形荧光墨水
invisible writing ink[印刷] 隐显墨水
invisible ink pen隐形笔
the use of invisible ink隐形墨水的使用
N（名词） a liquid used for writing that does not become visible until it has been treated with chemicals, heat, ultraviolet light, etc (需经过药品处理，加热或紫外光照射等方能显字的)隐显墨水