Yes, scrimshaw is engraving ivory, but it can be on bone as well. Although the orignins of the word is not really known, I always have associated the artform with the New England whaling industry of the 1800s, particularly Nantucket Island off of the coast of Massachusetts.
Whaling was an important industry as sperm (from sperm whales) and blubber from others was rendered down on ship to produce oil which was used as lamp oil or to make candles.
Whaling tours could last up to 5 years or more therefore to fight off boredom when the whales or the weather didn't cooperate, the sailors would carve or etch pictures into whale bone or ivory and then fill the lines with a contrasting substance to highlight the artwork.
Whalers in small boats would harpoon the whale and the boat and crew would be pulled along until the whale ultimatly tired and died. This became known as a "Nantucket Sleighride". One of my favorite rock bands of the 1960's, 'Mountain' penned a fantastic album and song, both entitled 'Nantucket Sleighride'
President John F. Kennedy was a collector of scrimshaw.
A Nantucket Sleighride to obtain blubber, oil and whalebone for scrimshaw.
'Mountain's' 1971 release entitled 'Nantucket Sleghride'
Yuri