1. Abnormally enlarged thyroid gland; can result from underproduction or overproduction of hormone or from a deficiency of iodine in the diet
   - goiter [N. Amer], goitre [Brit, Cdn], struma

Type of: disease

• genus Arnoseris
• genus Arrhenatherum
• genus Artamus
• genus Artemia
• genus Artemisia
• genus Arthropteris
• genus Artocarpus
• genus Arum
• genus Arundinaria
• genus Arundo
• genus Arvicola
• genus Asarum
• genus Ascaphus
• genus Ascaridia
• genus Ascaris
• genus Asclepias
• genus Ascophyllum
• genus Asimina
• genus Asio
• genus Aspalathus
• genus Asparagus
• genus Aspergillus
• genus Asperula
• genus Asphodeline
• genus Asphodelus