1. Elementary, primary, rudimentary refer to what is basic and fundamental. Elementary refers to the introductory, simple, easy facts or parts of a subject that must necessarily be learned first in order to understand succeeding ones: elementary arithmetic. Primary may mean much the same as elementary; however, it usually emphasizes the idea of what comes first even more than that of simplicity: primary steps. Rudimentary applies to what is undeveloped or imperfect: a rudimentary form of government.

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