Meaning
The estimated time of arrival: when a shipment, a person or a result is expected.
Three examples from work
Shipment
ClientWhat's the ETA for the second truck?
YouAround 4 pm, traffic permitting.
Project
ManagerDo we have an ETA on the fix?
DeveloperEnd of day tomorrow.
Meeting
ColleagueAnna's late. Any ETA?
YouShe said ten minutes.