Is a 2nd Mortgage the same as a home equity line of credit?

 I am completing this part of our taxes:  Is this loan a home equity line of credit or a loan you've ever refinanced?  We have a 2nd mortgage. We have not refinanced.  Is a 2nd mortgage considered the same as a HELOC? I didn't think it was a HELOC as I do not believe we can access more money from it, as in I don't think it is a line of credit.