1Zoology A space separating teeth of different functions, especially that between the biting teeth (incisors and canines) and grinding teeth (premolars and molars) in rodents and ungulates.
‘As in the traversodonts, a large gap - the diastema - separated the incisors from the square cheek teeth (seven on each side).’
‘Incisors and canines are absent, but the anterior cheek teeth are enlarged, triangular in cross section, and canine-like. They are separated from the rest of the cheek teeth by a diastema.’
‘The bit sits in a part of the horse's mouth called the diastema, which is a section devoid of teeth that lies between the front incisors and the back pre-molars and molars.’
‘The canines are absent or vestigial, and a substantial diastema separates incisors and cheek teeth.’
‘If a horse has a narrower diastema, a smaller or flatter palate, and/or a fat or thick tongue, a thinner bit may be far more comfortable in that horse's mouth than a thick one.’
1.1A gap between a person's two upper front teeth.
Origin
Mid 19th century via late Latin from Greek diastēma ‘space between’.
Are You Learning English? Here Are Our Top English Tips