Which bacteria are characterized by a square arrangement after cell division?

The bacteria characterized by a square arrangement after cell division are referred to as tetracocci. This term specifically describes cocci that divide in two planes and arrange themselves in groups of four, resembling a square. This arrangement occurs as the cells remain attached after division, which is a distinct feature of their reproductive pattern.

In contrast, streptococci form chains of spherical bacteria due to division in one plane, and diplococci present as pairs, resulting from division in one plane but remaining paired. Vibrio refers to rod-shaped bacteria that are curved, rather than forming any specific geometric arrangement associated with cocci. Therefore, tetracocci is the correct answer, as they uniquely form the square structure after division.