Definition
MNT is a NOTAM and aeronautical contraction meaning to monitor, the act of monitoring, or having monitored — that is, to listen to or watch a specified frequency, system, or condition continuously without necessarily transmitting or actively engaging with it.
Plain English
Short for 'monitor.' It tells the pilot to keep listening to a particular radio frequency or keep an eye on something, without needing to talk on it or take action unless required.
Context Anchor
Seen in NOTAMs and other shortened aviation text where space is limited.
Derivation
From the Latin monere, meaning 'to warn' or 'to remind.' A monitor was originally something or someone that gave warnings. In aviation, the sense carries through: you keep watch or keep listening so you'll catch any warning or instruction that comes through.
Why Pilots Care
When ATC or a NOTAM tells you to monitor a frequency, you are expected to be tuned in and listening — not transmitting unless called. Missing a monitored call can mean missing a clearance change, a traffic alert, or an emergency broadcast.
Intuition Check
Do not assume monitor means to transmit or take control. In this context, it usually means to listen to or watch something for information unless another instruction says more.
Example Sentence 1
After being handed off, the controller said, 'Monitor tower on 118.3' — so the pilot tuned in and listened without checking in.
Example Sentence 2
A NOTAM required all aircraft to MNT 121.5 while operating in the area.