Yes. When you subtract two, you get two congruent sides.
It can have two congruent sides but does not have to.
A triangle with two congruent sides is an isoscelestriangle. But an equilateral triangle has two congruent sides. (It actually has three congruent sides.) And isosceles triangle is generally described as a triangle with exactly two congruent sides.
Yes a square has two congruent sides.
A trapezoid with two congruent, opposite sides is an isosceles trapezoid.
No congruent sides is a scalene, two congruent sides is an isosceles triangle, three is an equilateral.
An isosceles triangle has two congruent sides.
It has two congruent sides
Two of the sides of an iscosceles are congruent.
Only if the congruent angle is the angle between the two congruent sides (SAS postulate).
A parallelogram cannot have only two congruent sides, nor only two congruent angles.
Diamond
A parallelogram has two pairs of congruent sides.