ait

noun2

1. •
   An island in a river, especially the River Thames in England.

   • The ait where the osiers grew. — 1649
2. •
   (Scotland) An oat.

noun4

1. •
   Initialism of allergen immunotherapy.
2. •
   Initialism of autoignition temperature.
3. •
   Initialism of alloimmune thrombocytopenia: a too-low number of platelets in the blood, especially of a newborn or fetus, due to alloimmunity.
4. •
   Initialism of auditory integration training.