Cubicula.
The accusative of the word "cubiculum" in Latin is "cubiculum." This is because "cubiculum" is a neuter noun in the second declension, which means that the accusative form is the same as the nominative form.
Cubiculum
bedroom
cella cellula cubiculum
parva cubiculum
Forum---Plural Form Forums,Foreign Plural Form Forumina
Linguae.
The Latin masculine noun draco (a snake) has the nominative plural form dracones
Gladioli (actual Latin plural) or gladioluses (Anglicized).
The plural of vertebra is vertebrae.
Actually, the plural form radiuses is accepted as correct and has found it's way into dictionaries (see the link below). The word radius and the plural radii are derived from the Latin word radius, a word for the spoke of a wheel. The plural form is a standard form for a plural in Latin.
culinae