What does 'ETL' stand for in data analytics?

Extract means to pull data from heterogeneous sources (CBS, ATM switch, mobile banking, CRM, external bureaus) in various formats (SQL databases, flat files, APIs, XML, JSON). Transform means data cleaning (null handling, deduplication, standardization   of date formats, currency), business rule application (calculate derived fields like LTV ratio), joining datasets, aggregation. Load means to write to target (Snowflake, Redshift, Azure Synapse, on-premise Oracle DWH).  Modern ELT (Extract, Load, Transform) loads raw data first into cloud data lakes, then transforms on-demand using tools such as Informatica, Talend, Apache Spark and dbt.