1.
If you come under attack or pressure, for example, people attack you or put pressure on you.
His relationship with the KGB came under scrutiny.
PHRASAL VERB : no passive , V P n
2.
If something comes under a particular authority, it is managed or controlled by that authority.
They were neglected before because they did not come under the Ministry of Defence.
PHRASAL VERB : no passive , V P n
3.
If something comes under a particular heading, it is in the category mentioned.
There was more news about Britain, but it came under the heading of human interest.
PHRASAL VERB : no passive , V P n