Chiefly Whaling. A vital or vulnerable point of an animal's body; = life-spot n. at compounds 3. Now chiefly historical.

(a) adj. consisting of the tympanic bone and periotic bones united; (b) n. a tympanoperiotic bone, as the ear-bone of a cetacean.

= sense 3.

Zoology. A rounded organ found in the head of many toothed whales, which is made of a waxy material and is believed to focus acoustic signals…