Et al. is a Latin abbreviation meaning “and others.” Writers use it in citations and references when a work has multiple authors but they don't want to list every single name. If five scientists write a research paper together, instead of writing out all their names every time, you might write “Johnson et al. discovered...” after mentioning Johnson and the team once with all names included.

In modern English we use et al. in citations for works with multiple authors. Notice the period after “al” because it's an abbreviation, but no period after “et” because that's the complete Latin word for “and.”

You'll see et al. most often in academic writing, scientific papers, and bibliographies. It saves space and keeps things readable when many people contributed to a single work. Scientists use it constantly because research today often involves large teams. The phrase acknowledges that while we're mentioning one person's name, we recognize others did important work too.