A search parameter that defines a named search item that can be used to search/filter on a resource.

SearchParameter
url
Canonical identifier for this search parameter, represented as a URI (globally unique)
identifier
Additional identifier for the search parameter (business identifier)
version
Business version of the search parameter
versionAlgorithm[x]
How to compare versions
name
Name for this search parameter (computer friendly)
title
Name for this search parameter (human friendly)
derivedFrom
Original definition for the search parameter
status
draft | active | retired | unknown
experimental
For testing purposes, not real usage
date
Date last changed
publisher
Name of the publisher/steward (organization or individual)
contact
Contact details for the publisher
description
Natural language description of the search parameter
useContext
The context that the content is intended to support
jurisdiction
Intended jurisdiction for search parameter (if applicable)
purpose
Why this search parameter is defined
copyrightLabel
Copyright holder and year(s)
code
Recommended name for parameter in search url
base
The resource type(s) this search parameter applies to
type
number | date | string | token | reference | composite | quantity | uri | special
expression
FHIRPath expression that extracts the values
processingMode
normal | phonetic | other
constraint
FHIRPath expression that constraints the usage of this SearchParamete
target
Types of resource (if a resource reference)
multipleOr
Allow multiple values per parameter (or)
multipleAnd
Allow multiple parameters (and)
comparator
eq | ne | gt | lt | ge | le | sa | eb | ap
modifier
missing | exact | contains | not | text | in | not-in | below | above | type | identifier | of-type | code-text | text-advanced | iterate
chain
Chained names supported
component
For Composite resources to define the parts
definition
Defines how the part works
expression
Subexpression relative to main expression