When a call made to Word.run function, I am getting 'Word' is undefined in word 2016

Question

Issue:

• Here I am using an word add-in in word 2016. When a call a function which uses Word.run is giving an error as 'Word' is undefined.
• The add-in file is working properly in office 365 desktop application as well as in browser.

NOTE: I am initialising word before calling the Word.run

What I have Checked?

• Cleared the cache and checked out.

• Version of Office-js is latest.

• Using latest schema in xml i.e 1.1.

• All the resources are defined properly in xml file.

The function call is made from a html page to a js page where the Word.run will execute. the office is initialised in the html page when the page get's loaded.