All 3 Uses of

garnish

in

Moby Dick

All round, her unpanelled, open bulwarks were garnished like one continuous jaw, with the long sharp teeth of the sperm whale, inserted there for pins, to fasten her old hempen thews and tendons to.†
Chpt 16-18 *

…seen a sailor who had visited that very island, and he told me that it was the custom, when a great battle had been gained there, to barbecue all the slain in the yard or garden of the victor; and then, one by one, they were placed in great wooden trenchers, and garnished round like a pilau, with breadfruit and cocoanuts; and with some parsley in their mouths, were sent round with the victor's compliments to all his friends, just as though these presents were so many Christmas turkeys.†
Chpt 16-18

"Speak, thou vast and venerable head," muttered Ahab, "which, though ungarnished with a beard, yet here and there lookest hoary with mosses; speak, mighty head, and tell us the secret thing that is in thee.†
Chpt 70-72

Definition:

(garnish as in: garnished with parsley)
to decorate or adorn something (most typically food with another food); or the item added for decoration