Answer:
The "senior moment" comment is known as a micro-aggression.
Explanation:
A micro-aggression refers to a brief interaction between individuals from different backgrounds, ethnicities, age, etc. It is understood as a non-physical aggression and it would tend to be overlooked.
It tends to be a comment which does not feel light-hearted; it tend to hurt the receiving individual and could even not be meant as an aggression by the sender.
In this case, Thomas is 65 years old so he can tend to forget certain things, by saying the "senior moment" comment, his supervisor is providing a micro-aggression to him by pointing out that his forgetfulness is due to his age, which is something Thomas cannot do anything about so he has to brush it away with a simple laugh.
