Question

Is a rhombus sometimes a square

Answer 1

So,

A rhombus is a quadrilateral with four equal sides.  This means that all four sides are of equal lengths.  So each side is the same length.  A rhombus's vertices do not have to be any particular angle.

A square is a special case.  It is both a rectangle and a rhombus because it has four right angles (rectangle) and four equal sides (rhombus).

So is a rhombus sometimes a square?  Yes, when its angles equal 90°.  No, when its angles do not equal 90°.  So a rhombus can SOMETIMES be a square.