- Type is a mechanism to store different data in the same index
- Types help reducing number of indices for previously discussed performance reasons
- Searching across types within index and between shards adds no overhead
- Lucene implications - field that exists in one type will consume resources in other types
- Fields across types in an index must use consistent data types, e.g. string or number, not string and number
- Score for search results calculated at the index level
- Mapping for document's properties are defined at the type level
- Search and aggregation can be executed at type, index, alias, multi-index, or cluster levels