Main Entry: tail

Pronunciation: \ˈtā(ə)l\

Function: noun

Usage: often attrib

1 : the rear end or a process or prolongation of the rear end of the body of an animal

[tail illustration]

2 : one end of a molecule regarded as opposite to the head ; especially : the end of a lipid molecule that consists of a nonpolar hydrocarbon chain and is opposite to the polar group <most surface-active agents have a long hydrophobic tail attached to a polar head—R. E. Kirk & D. F. Othmer>
3 : any of various parts of bodily structures that are terminal: as a : the distal tendon of a muscle b : the slender left end of the human pancreas c : the common convoluted tube that forms the lower part of the epididymis
4 : the motile part of a sperm that extends from the middle piece to the end and comprises the flagellum
5 : a thin protein tube which forms part of the coat of some bacteriophages and through which DNA is injected into a cell

—tailed \ˈtā(ə)ld\ adjective

—tail·less \ˈtā(ə)l-les\ adjective