I know what this means, but can't figure out why ponds, lakes, or oceans might be referred to as "the drink."
From Wiktionary:
(colloquial, with the) Any body of water.
If he doesn't pay off the mafia, he’ll wear cement shoes to the bottom of the drink!
Best Answer
OED1 (1897) has the following in its entry for the noun drink:
Thus, reference to a large body of water as a drink was established by the 1850's. But such usage as in the drink may be somewhat older than that. OED1's second main entry for the verb drink is like
Cites for adrink are dated from 880 AD to 1300 AD. Aphesis refers to loss of the initial unstressed vowel of a word. Drink as the verb to drown was formed from the older word adrink, which if interpreted as an adverb could suggest in the drink.