Characterized by the presence or operation of a definite rule or set of rules; marked or distinguished by evenness, order, or harmony in character…

Of an action, pursuit, procedure, etc.: characterized by method or order; performed or carried on systematically or meticulously. Of discourse, etc…

Of an action, pursuit, discourse, etc.: characterized by method or order; = methodical, adj. 1a; relating to method. Also (occasionally) of a person…

Arranged or conducted according to a system, plan, or organized method; involving or observing a system; (of a person) acting according to system…

In extended use: systematic, methodical, meticulous.