rickets

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A bone disease of children marked by bone demineralization and defective bone growth, caused usually by a deficiency of or an impaired metabolism of vitamin D.

from The Century Dictionary.

• noun A disease, technically called rachitis. See rachitis, .

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Med.) A disease which affects children, and which is characterized by a bulky head, crooked spine and limbs, depressed ribs, enlarged and spongy articular epiphyses, tumid abdomen, and short stature, together with clear and often premature mental faculties. The essential cause of the disease appears to be the nondeposition of earthy salts in the osteoid tissues. Children afflicted with this malady stand and walk unsteadily. Called also rachitis.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun pathology A disorder of infancy and early childhood caused by a deficiency of vitamin D, causing soft bones.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun childhood disease caused by deficiency of vitamin D and sunlight associated with impaired metabolism of calcium and phosphorus