# Definitions
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+  **Domain:** The primary container for all OpenSearch resources. It represents the entire environment where your data is stored and indexed. 
+  **Node:** A single instance of OpenSearch running within your domain. Nodes work together to form a cluster and distribute the workloads and data among them. 
+  **Leader nodes:** Nodes that perform cluster management tasks but do not hold data or respond to data requests. 
+  **Dedicated leader nodes:** Nodes that serve exclusively as specialized nodes that are configured to perform the role of a leader. 
+  **Data nodes:** Nodes that are responsible for storing and managing data. Data nodes handle indexing and searching operations and store the actual index and document data. 
+  **UltraWarm and cold nodes:** UltraWarm nodes provide a cost-effective way to store large amounts of read-only data on Amazon OpenSearch Service. Rather than attached storage, UltraWarm nodes use Amazon S3 and a sophisticated caching solution to improve performance. 
+  **Multi-AZ with Standby:** A deployment option for Amazon OpenSearch Service domains providing 99.99% availability and consistent performance by spanning three Availability Zones, each with a complete data copy. 
+  **Index:** A data structure used to store, organize, and search documents, similar to a database table. 
+  **Shard:** A smaller, more manageable segment of an index. Each shard acts as a self-contained index, and in Amazon OpenSearch Service, shards are distributed across data nodes for load balancing, redundancy, and fault tolerance. 
+  **Replica:** A duplication of a shard, offering failover and load balancing capabilities. Amazon OpenSearch Service automatically distributes replica shards across various nodes within the domain. 
+  **Document:** A single unit of searchable data, like a row in a database table. Each document possesses a unique identification (ID) and encompasses a set of fields. 
+  **Field:** A named, typed value within a document, resembling a column in a database table. Fields may have various data types, including string, number, date, or Boolean. 
+  **Mapping:** Defines the structure of documents in an index, including field names, data types, and other metadata. It acts as a schema for the documents and helps Amazon OpenSearch Service understand the data and optimize search performance. 
+  **Query:** A request to search, filter, or aggregate data from an OpenSearch index. Amazon OpenSearch Service accommodates various query types, including term, match, range, and Boolean queries. 
+  **Aggregation:** A process of grouping and summarizing data based on specified criteria. OpenSearch supports various aggregation types, such as bucket aggregations, metric aggregations, and pipeline aggregations. 
+  **Snapshot:** Refers to a point-in-time copy of the data in one or more indices. It is essentially a backup mechanism that captures the state of your data at a specific moment.