new life form for Latin?

[Mark A Mandel]

The term's obviously been formed in English (or possibly another modern
language) on analogy to "in vivo" and "in vitro", because it isn't good
Latin.

"*In silico" would come from a nonexistent 2nd declension noun "silicus"
or "silicum". The name of the element silicon is derived (AHD4) from New
Latin "silica", the stuff of quartz, sand, etc., which in turn comes
from Classical Latin "silex" 'flint'. These two nouns yield the phrases
"in silica" (with long a) and "in silice" respectively.

-- Mark A. Mandel