• A fungal infection of the nail, usually caused by DERMATOPHYTES; YEASTS; or nondermatophyte MOLDS.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2021
• A fungal infection of the toenails or fingernails that tends to cause the nails to thicken, discolor, disfigure, and split.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2021
• Fungal infection of a fingernail or toenail.
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• Toenail fungus.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• Onychomycosis is fungal infection of the nail plate, nail bed, or both. The nails typically are deformed and discolored white or yellow. Diagnosis is by appearance, wet mount, culture, polymerase chain reaction, or a combination. Treatment, when indicated, is with oral terbinafine or itraconazole.
  Merck Manuals
  Merck & Co., Inc., 2020
• Onychomycosis is a fungal infection of the toenails or fingernails that may involve any component of the nail unit, including the matrix, bed, or plate. Onychomycosis can cause pain, discomfort, and disfigurement and may produce serious physical and occupational limitations, as well as reducing quality of life.
  Medscape
  WebMD, 2019
• Nail fungus is a common condition that begins as a white or yellow spot under the tip of your fingernail or toenail. As the fungal infection goes deeper, nail fungus may cause your nail to discolor, thicken and crumble at the edge. It can affect several nails.
  Mayo Clinic
  Mayo Foundation for Medical Education and Research