Idioms are so much a part of our language that we use them without thinking. Their meaning has become second nature with us and we rarely stop to think why an idiom means what it does. One example is the phrase ” long in the tooth” which means ” getting on in years” or ” elderly”. I had always thought that it had to do with the fact that a horse’s teeth never stop growing . The older the horse, the longer it’s teeth. That’s why, at horse fairs, horse buyers open the horse’s mouth to see how long the teeth are and are thus able to gauge it’s age.
Recently, I came across another explanation. In the case of humans,unlike horses our teeth stop growing after a certain age. However, as we grow older, the gums shrink unless they are brushed extra carefully. As the gums recede , the teeth appear longer . Hence “long in the tooth”. Neat , huh ?