Outside the fixed compound 囹圄 ('prison'), this character has no independent use. It is filed only as 'used in 囹圄'. The compound itself is literary and shows up in news clichés like 身陷囹圄 ('thrown into jail') when describing fallen officials.
memory
The outer 囗 is a walled enclosure (think prison walls); the inside is 令 'order/command', which here just supplies the sound líng. So: walls + a command-sounding component = the literary word for the place you go when an official command locks you up.
Kangxi #31, the 'enclosure' radical - four walls drawn around whatever is locked inside. Note the strokes are non-contiguous: the top and left walls go down first, then the inside 令 is written, and only at the very end does the bottom wall close the box. Same wrap-then-close order as 国 and 回.
Pure phonetic - 令 contributes the sound (lìng to líng, just a tone shift) with no semantic role. The same phonetic series gives 玲, 铃, 零 and 领 - all reliably read líng/lǐng.
