If the WORD window size is small, FONT drop down list isn't shown.By clicking on appropriate group from RIBBON, dialogue window is opened containing elements of the group that weren't displayed.
Displaying FONT drop-down list while window dimensions are small, steps:
Select appropriate TAB in RIBBON-u (HOME TAB in this case);
Click on the FONT group arrow;
Dialogue window is opened containing group elements that weren't displayed;