Eleventh-hour and Zero hour

Zero hour and eleventh-hour are semantically related. in latest possible moment topic. In some cases you can use "Zero hour" instead a noun phrase "Eleventh-hour".

Zero hour noun - A time or state of affairs requiring prompt or decisive action.

Eleventh-hour and zero hour are semantically related. Sometimes you can replace phrase "Eleventh-hour" with "Zero hour", this phrases are similar.