Ollie

From Germanic, from Latin olivarius (“olive tree”) (from oliva (“olive”)), and from Welsh.

Ollie

1. A diminutive of the male given name Oliver.
2. A diminutive of the female given names Olivia, Olive and Olwen.
   • 1994 Robertson Davies, The Cunning Man, Viking 1995, →ISBN, page 429:

     To my surprise and pleasure, it was Olwen that Esme chose to use when speaking of, and to, the baby - though she showed an unhappy tendency to shorten it to Ollie, in spite of my protests that this brought to mind not a stately princess, but the fat man in the Laurel and Hardy comedy series.

Ollie

1. A diminutive of the male given name Oliver
2. A diminutive of the male given name Olivier