To teach is simply to communicate knowledge; to instruct (originally, to build in or into, put in order) is to impart knowledge with special method and completeness; instruct has also an authoritative sense nearly equivalent to command. To educate is to draw out or develop harmoniously the mental powers, and, in the fullest sense, the moral powers as well. To train is to direct to a certain result powers already existing. Train is used in preference to educate when the reference is to the inferior animals or to the physical powers of man; as, to train a horse; to train the hand or eye. To discipline is to bring into habitual and complete subjection to authority; discipline is a severe word, and is often used as a euphemism for punish; to be thoroughly effective in war, soldiers must be disciplined as well as trained. To nurture is to furnish the care and sustenance necessary for physical, mental, and moral growth; nurture is a more tender and homelike word than educate. Compare EDUCATION.