ICD Hierarchical Term

**Semantic type:** Idea or Concept

**Definition:** Hierarchical terms (HTs) in the International Classification of Diseases (ICD) and ICD for Oncology (ICD-O) coding systems that serve to designate broad categories and establish the top levels of the ICD and ICD-O hierarchies. HTs are generally not used in clinical coding.

**Synonyms:** - HT - Hierarchical Term