1,2. Orderly, methodical, systematic characterize that which is neat, in order, and planned. These three words are sometimes used interchangeably. However, orderly emphasizes neatness of arrangement: an orderly array of books. Methodical suggests a logical plan, a definite order of actions or method from beginning to end: a methodical examination. Systematic suggests thoroughness, an extensive and detailed plan, together with regularity of action: a systematic review.