Yes, I do consider them the same.  And you’ve asked the question correctly because Secaucus is a city and the Meadowlands is an area, technically a huge tract of marshlands that still remain mostly undeveloped in the northeast area of NJ and just a few miles west of New York City.  

Secaucus borders the Meadowlands as does a handful of other cities, but over time Secaucus and the Meadowlands became mostly synonymous (except for locals who are more specific geographically).  

As a hobbyist, if anyone is referring to Secaucus or the Meadowlands, that means to me to be in that general area around Exit 16 off the NJ Turnpike, along Route 3 or any of its access roads like Paterson Plank Road, Mill Creek Road, etc.  

Yes most do consider Seacaucus as the same meadowlands. In my experience those who say their in the meadowlands are usually in the East Rutherford MetLife area though.