K-shell

[key-shel] /ˈkeɪˌʃɛl/

noun, Physics.
1.
the first shell of electrons surrounding the nucleus of an atom and containing, when filled, two electrons having principal quantum number 1.

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Ksi
1. one thousand pounds per square inch.
Ksl
Knowledge Systems Laboratory
Ksr
1. Keyboard Send Receive. 2. Kendall Square Research. (1995-11-23)

K-star
noun, Astronomy. 1. a relatively cool, orange-to-red star, as Aldebaran or Arcturus, having a surface temperature between 3500 and 5000 K and an absorption spectrum with strong lines of calcium and many neutral metals.
Kstj
abbreviation 1. Knight of the Order of St John