ELT

ELT is an acronym that has several meanings across different domains. In data management, ELT stands for Extract, Load, Transform. This approach first extracts data from source systems, loads it into a target repository such as a data warehouse or data lake, and then performs transformations within the destination environment. ELT contrasts with traditional ETL, where transformation occurs before loading. Proponents argue that ELT leverages the target system’s compute and storage capabilities, simplifies data pipelines in cloud architectures, and supports rapid access to raw data for analysis. Critics point to reliance on powerful destinations and potential data governance challenges if transformations are not carefully managed.

ELT is also widely used to denote English Language Teaching, the field focused on teaching English to non-native speakers. It encompasses curriculum design, pedagogy, assessment, and teacher professional development. ELT programs operate in schools, universities, language institutes, and online platforms, spanning tasks such as listening and speaking practice, grammar instruction, and intercultural communication. The field combines procedural routines with standards-based assessment to support communicative competence and academic or professional goals.

Another notable usage is the European Extremely Large Telescope, referred to as ESO's ELT. Under construction in Chile by the European Southern Observatory, it features a 39-meter primary mirror and advanced adaptive optics. The telescope is designed to enable high-resolution observations in optical and near-infrared wavelengths, addressing questions about planet formation, stellar evolution, dark matter, and the early universe. The ELT represents a major step in ground-based astronomy and is expected to begin scientific operations after a commissioning phase.