a very large toothed whale (physeter macrocephalus), having a head of enormous size. the upper jaw is destitute of teeth. in the upper part of the head, above the skull, there is a large cavity, or case, filled with oil and spermaceti. this whale sometimes grows to the length of more than eighty feet. it is found in the warmer parts of all the oceans. called also cachalot, and spermaceti whale.