fiduciary: Definition from Dictionary.com

Get the definition for fiduciary: http://www.dictionary.com/browse/fiduciary at Dictionary.com

Trump has been using this word a lot today. Getting the feeling after reading the definition that he may be using it incorrectly. Not sure; I’m just a layman. 

When I have money put into my 401k, for example, wish could trust that the firm investing the money on my behalf has a sense of fiduciary responsibility. But, I’m not sure if that’s correct. They know I’m participating in thier selection of mutual funds in an effort to save toward a “working retirement”, and ‘they’ understand investment markets better than i do. I rely on them being good, honest, and professional. 

Is Trump conflating his roles as business owner and father as a “fiduciary responsibility”? I don’t know, I’m asking.