Hadoop Ecosystem is neither a programming language nor a service, it is a platform or framework which solves big data problems. You can consider it as a suite which encompasses a number of services (ingesting, storing, analyzing and maintaining) inside it. This ecosystem comprises of multiple components such as:
- 
HDFS
 
- 
MapReduce
 
- 
Hive
 
- 
Spark
 
- 
HBase
 
- 
YARN etc.
 
Each of these components have their own use cases. As a whole, it can be used with big data.