How can I stop a trigger from triggering another trigger that gets invoked when we are updating child object from a trigger on parent object?

Hello Rachit,

On the assumption that your delete logic is embedded in the Child trigger and you want to execute that logic upon some event in the Parent object ....

Triggers can only be invoked when a DML statement occurs and the trigger is registered to handle that DML event (insert, update, delete, undelete - and in before/after such event)
Move your logic out of the Child trigger into a class that can be called both from the Child trigger and from the Parent trigger