What are the plural forms of curriculum and which part of the dictionary did you use to find the answer

The word 'curriculum' is came from Latin, and that means that there is no only one stable plural form. As language develops, it becomes simpler, so nowadays in every single dictionary you can come across 'curriculums' with simply added 's'. The original plural form of latin words must be learnt by heart, and curriculum is curricula (mostly used in official documents/scientific works). Both are possible.