long [OE] The long referring to length and the long meaning ‘to desire’ are unrelated, though both have ancient Germanic roots. The phrase long in the tooth [M19th] was first used to describe horses, and comes from the way you can estimate a horse’s age by looking at its teeth: if the gums have receded and the teeth consequently look very long, you know the animal is rather old. See also gift. The background to long time no see, would nowadays probably be seen as politically incorrect. It was originally an American expression and arose in the early 20th century as a supposedly humorous imitation of the broken English spoken by a Native American. This dubious past is long forgotten and the phrase is now freely used on both sides of the Atlantic. See also arm.