What does $\Lsh$ mean?
This picture was introduced with the version of 16:08, 10 June 2016 with the comment "Replacing the typed formulae with the picture formulae". This replacement went wrong.
The previous version of 07:45, 11 April 2016 still uses the string
γ = Cp/ Cv
The link heat ratio in the text refernces a page with the picture
So the correct formula seems to be
$$\gamma=\frac{C_P}{C_V}$$
I therefore changed this in the Wikipedia article, Version of 00:00, 20 April 2017
Typographical / transcription error? Follow the link to "Heat capacity ratio" and you see the formula $$\gamma=\frac{C_P}{C_V}.$$ That weird \Lsh
symbol looks vaguely like the TeX gamma. And so does $Y$.