What is this bottle?

This is a strange bottle shape to me. Found on a river in Jacksonville, FL. Anyone have any idea what it is?

In a word, olives.

This picture comes from this etsy page

https://www.etsy.com/au/listing/640386630/vintage-set-of-4-food-bottles

Yours has a valve mark on the base which dates it to earlier 20th century

Condiments such as olives, cocktail onions, cherries, etc. from the early mid-20th Century, I'd guess.