Not sure why you are downvoted, this is straight out of Larry Page’s letter to the public about the restructuring.

> We liked the name Alphabet because it means a collection of letters that represent language, one of humanity’s most important innovations, and is the core of how we index with Google search! We also like that it means alpha‑bet (Alpha is investment return above benchmark), which we strive for! I should add that we are not intending for this to be a big consumer brand with related products—the whole point is that Alphabet companies should have independence and develop their own brands.

https://abc.xyz/

Completely off-topic, but in the face of all this corporatism, I still love the fact that the period at the end of the sentence, "Sergey and I are seriously in the business of starting new things. Alphabet will also include our X lab, which incubates new efforts like Wing, our drone delivery effort." is a link to http://hooli.xyz

No they're referring to their mountaineering tendencies, their "Alp habet".

As this reorg was Ruth’s Noogler project, she came from the investment banking world where seeking alpha is the name of the game…so making bets to yield alpha is pretty much what the company does.