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docs/content/concepts/solids-pipelines/solids.mdx

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A solid only starts to execute once all of its inputs have been resolved. Inputs can be resolved in two ways:		A solid only starts to execute once all of its inputs have been resolved. Inputs can be resolved in two ways:

- The upstream output that the input depends on has been successfully emitted and stored.		- The upstream output that the input depends on has been successfully emitted and stored.
- The input was stubbed through config.		- The input was stubbed through config.

You can use a [Dagster Type](/concepts/types) to provide a function that validates a solid's input every time the solid runs. In this case, you use <PyObject object="InputDefinition" pluralize /> corresponding to the decorated function arguments.		You can use a [Dagster Type](/concepts/types) to provide a function that validates a solid's input every time the solid runs. In this case, you use <PyObject object="InputDefinition" pluralize /> corresponding to the decorated function arguments.

```python file=/concepts/solids_pipelines/solids.py startafter=start_typed_input_solid_marker endbefore=end_typed_input_solid_marker		```python file=/concepts/solids_pipelines/solids.py startafter=start_typed_input_solid_marker endbefore=end_typed_input_solid_marker
MyDagsterType = DagsterType(type_check_fn=lambda _, value: value % 2 == 0, name="MyDagsterType")		MyDagsterType = DagsterType(
		type_check_fn=lambda _, value: value % 2 == 0, name="MyDagsterType"
		)


@solid(input_defs=[InputDefinition(name="abc", dagster_type=MyDagsterType)])		@solid(input_defs=[InputDefinition(name="abc", dagster_type=MyDagsterType)])
def my_typed_input_solid(abc):		def my_typed_input_solid(abc):
pass		pass
```		```

#### Outputs		#### Outputs
▲ Show 20 Lines • Show All 79 Lines • ▼ Show 20 Lines	Args:
args (any): One or more arguments used to generate the nwe solid		args (any): One or more arguments used to generate the nwe solid
name (str): The name of the new solid.		name (str): The name of the new solid.
input_defs (list[InputDefinition]): Any input definitions for the new solid. Default: None.		input_defs (list[InputDefinition]): Any input definitions for the new solid. Default: None.

Returns:		Returns:
function: The new solid.		function: The new solid.
"""		"""

@solid(name=name, input_defs=input_defs or [InputDefinition("start", Nothing)], **kwargs)		@solid(
		name=name,
		input_defs=input_defs or [InputDefinition("start", Nothing)],
		**kwargs,
		)
def _x_solid(context):		def _x_solid(context):
# Solid logic here		# Solid logic here
pass		pass

return _x_solid		return _x_solid
```		```

## FAQ		## FAQ

### Why "Solid"?		### Why "Solid"?

Why is a solid called a "solid"? It is a journey from a novel concept, to a familiar acronym, and back to a word.		Why is a solid called a "solid"? It is a journey from a novel concept, to a familiar acronym, and back to a word.

In a data management system, there are two broad categories of data: source data––meaning the data directly inputted by a user, gathered from an uncontrolled external system, or generated directly by a device––and computed data––data produced by computation over other data. Management of computed data is the primary concern of Dagster. Another name for computed data would be software-structured data. Or SSD. Given that SSD is already a well-known acronym for Solid State Drives we named our core concept for software-structured data a Solid.		In a data management system, there are two broad categories of data: source data––meaning the data directly inputted by a user, gathered from an uncontrolled external system, or generated directly by a device––and computed data––data produced by computation over other data. Management of computed data is the primary concern of Dagster. Another name for computed data would be software-structured data. Or SSD. Given that SSD is already a well-known acronym for Solid State Drives we named our core concept for software-structured data a Solid.