11B

noun3

1. •
   (US, slang) An infantryman.
2. •
   boron-11. The "11" should be superscript: ¹¹B.
3. •
   (Singapore, slang) An identity card used by a national serviceman, as opposed to one used by a civilian.

   • NSmen just have to present their SAF Identity Card (commonly known as 11B), or don their uniforms at stores displaying the "We Support NS" decal. — 2019