Is STOP AND ABORT are same IN INFORMATICA?

No both kill the process but the way is different, the process timeout period is the main difference in Stop and Abort.
Stop will Stop reading from the source and release the memory blocks that are occupied by the session at a time but it will continue updating and committing changes in target whereas abort also stop reading but it has the timeout period of 60 sec. If the session fails to update or commit the changes within 60 sec then the session will be aborted by terminating the DTM process thread and it will not release the memory immediately.
To ensure Data Consistency Stop Will try to Rollback data but in Abort kill the process immediately so that can’t be rolled back.