The Collaborative International Dictionary
Sperm \Sperm\, n.[Contr. fr. spermaceti.] Spermaceti.
Sperm oil, a fatty oil found as a liquid, with spermaceti, in the head cavities of the sperm whale.
Sperm whale. (Zo["o]l.) See in the Vocabulary.
Wiktionary
n. whale oil from a sperm whale
WordNet
n. an animal oil found in the blubber of the sperm whale
Wikipedia
Sperm oil is a waxy liquid obtained from sperm whales. It is a clear, yellowish liquid with a very faint odor. Sperm oil has a different composition from common whale oil. Although it is traditionally called an "oil", it is technically a liquid wax. It is composed of wax esters with a small proportion of triglycerides, an ester of an unsaturated fatty acid and a branched-chain fatty alcohol. It is a natural antioxidant and heat-transfer agent. Through catalytic reaction, it carries phosphorus and sulfur derivatives providing anti-wear and friction modification. In the late 18th and early 19th centuries, sperm oil was prized as an illuminant for its bright, odorless flame and as a lubricant for its low viscosity and stability. It was supplanted in the late 19th century by alternatives such as kerosene and petroleum-based lubricants, following bans on both whaling and the subsequent sale and use of whale-derived products.
The oil from bottlenose whales was sometimes called "Arctic sperm oil". It was cheaper and inferior to true sperm oil.