Difference between Ethernet & Automotive Ethernet
Automotive Ethernet is a subcategory of Ethernet as specified in IEEE 802.3. It operates over a single differential pair of wires, and is specifically designed for the low radiated emissions and immunity requirements of the automotive industry. The distance which these standards operate is also much shorter than other Ethernet standards, given the size of the vehicles they are intended to be used in.
Ethernet flavors considered as Automotive include:

10BASE-T1S 802.3cg-2019 Clauses 147 &amp; 148 10Mbit/s point-to-point over 15m, or up to 8 nodes on a 25m mixing segment.
100BASE-T1 802.3bw-2015 Clause 96 100Mbit/s over 15m single copper pair cable
1000BASE-T1 802.3bp-2016 Clauses 97 &amp; 98 1000Mbit/s over 15m (or an optional extended 40m reach) single copper pair cable
2.5/5/10GBASE-T1 802.3ch-2020 clause 149 2.5Gbit/s 5Gbit/s and 10Gbit/s over 15m single copper pair cable

A new 802.3cy automotive Ethernet standard is in the works to provide connectivity greater than 10 Gbit/s.
These Ethernet standards are not only applicable to automotive, however, as they are found very useful in industrial automation, building controls, and backplane applications.
An Automotive Electronics Council (AEC) rating indicates that a specific electrical component has been qualified for use in the stringent environmental of an automobile. A component implementing one of the above mentioned Ethernet standard may not be AEC qualified for use in an automobile, although they typically are. Similarly, there are many non-Ethernet devices (such as microcontrollers, CAN transceivers, etc.) that are AEC qualified.