轻书 It literally means light book symbolizing the idea of recording thoughts

Relation Nicknames

拈支素笔 [niān zhī sù bĭ]
拈支素笔 evokes an image of picking up a simple writing brush suggesting an intention to record thoughts ...
入书笺 [rù shū jiān]
It translates to into the book letternote expressing a sense of recording something into literature ...
无言簿 [wú yán bù]
Silent Notebook signifies someone who keeps their thoughts to themselves A book full of unsaid words ...