Maximum transmission unit - Wikipedia
https://en.wikipedia.org/wiki/Maximum_transmission_unit
In computer networking, the maximum transmission unit (MTU) is the size of the largest protocol data unit (PDU) that can be communicated in a single network layer transaction. The MTU relates to, but is not identical to the maximum frame size that can be transported on the data link layer...
Manual:Maximum Transmission Unit on RouterBoards - MikroTik Wiki
https://wiki.mikrotik.com/wiki/Manual:Maximum_Transmission_Unit_on_RouterBoards
2 MTU on RouterOS. 2.1 Full frame MTU. It is sole responsibility of administrator to configure MTUs such that intended services and applications can be successfully implemented in network.
What is MTU (maximum transmission unit)? | Cloudflare
https://www.cloudflare.com/learning/network-layer/what-is-mtu/
Maximum transmission unit, or MTU, limits data packet size for any networked device. Learn about IP fragmentation and how MTU network settings affect packets.