Defintion:
ESL: ESL stands for English as a Second Language, though in schools, ESL often is the name by which intervention programs for ESL students are known.
Example of Usage: Have you referred your new exchange student for ESL services yet?
Also Known As: ELL (English Language Learners); EFL (English as a Foreign Language); EFOL (English for Speakers of Other Languages)
Related Resources:
About.com's English as a 2nd Language website