An expression is a structured combination of one or more concept identifiers used to represent a clinical meaning. SNOMED CT postcoordinated expressions enable clinical meanings to be represented, which cannot be represented using a single SNOMED CT concept. For example, the following postcoordinated expression represents 'pain in the left thumb:

53057004 |hand pain| :
	363698007 |finding site| = (76505004 |thumb structure| :
		272741003 |laterality| = 7771000 |left| )

SNOMED CT postcoordinated expressions allow analytics services to perform meaning-based queries over a more extensive set of clinical meanings than just individual concepts.