Classification-Index

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Classification 2025 Summer Edition

Worldwide source of medical classification resources

Class Index

← Previous

...

Oncoviruses See Retroviridae

Oncoviruses, Type C See Retroviridae

Ondatra See Arvicolinae

Ondatra zibethicus See Arvicolinae

One Child Policy See Family Planning Policy

One Health WA 30.7

One Health Concept See One Health

One Health Initiative See One Health

One Medicine Initiative See One Health

One Parent Family See Single-Parent Family

One-Child Policy See Family Planning Policy

One-Parent Family See Single-Parent Family

One-Person Household See Family Characteristics

Onions

General

QK 495.L72

As medicinal plants

QV 766.5.L4

Geographic distribution

QV 770

Dietary use in health and disease

WB 430

Onkocristin See Vincristine

Onkodox See Doxorubicin

Onkofluor See Fluorouracil

Onkoposid See Etoposide

Onkotrone See Mitoxantrone

Onlay, Dental See Inlays

Onlays See Inlays

Onlays, Dental See Inlays

Online Bullying See Cyberbullying

Online Education See Education, Distance

Online Learning See Education, Distance

Online Mendelian Inheritance In Man See Databases, Genetic

HM 742 - HM 743

Health related

WA 590

See Social Support

Online Systems Z 699

By subject

Z 699.5.A - Z Z

In medicine (General)

W 26.55.I4

In other special fields (Form number 26.5 in any NLM schedule where applicable)

Only Child

Parenting

WS 105.5.C3

Psychology

WS 105.5.F2

Only Children See Only Child

Onodi Air Cell See Ethmoid Sinus

Ontogeny See Developmental Biology

Onxol See Paclitaxel

Onychocryptosis See Nails, Ingrown

Onychomycosis WR 475

Onychophagia See Nail Biting

Oocytes WP 100

Oogenesis QU 380

Oophorectomy See Ovariectomy

Oophoritis WP 320

Ootorhinolaryngeal Neoplasms See Otorhinolaryngologic Neoplasms

Opaque Media See Contrast Media

Open Access to Information See Access to Information

Open Bite WU 440

Open Fractures See Fractures, Open

Open Head Injury See Craniocerebral Trauma

Open Source Software See Software

Open Spine See Spinal Dysraphism

Open-Angle Glaucoma See Glaucoma, Open-Angle