Question

what is the difference between fringe spacing and fringe width ​

Answer 1

Fringe width is the breadth (horizontal) dimension of the fringe (slit) wheres distance between two fringes is simply the spacing between two slits

Answer 2

Fringe width is the breadth (horizontal) dimension of the fringe (slit) wheres distance between two fringes is simply the spacing between two slits.

{By the way I did not copy anyone it was in my eledr sister's notebook}