customer (17 facts) (client) - A person who make decisions about ordering and paying for software (in contrast to user); customers are those who have the problem that is being solved by the development of software
domain expert (3 facts) - Somebody with expertise in a given domain, but who may or may not have expertise in software
engineer (3 kinds, 13 facts) - A person who performs engineering (in contrast to scientist). The term engineer is legally reserved, in many jurisdictions, for those who have obtained engineering education and experience, and perform engineering within a company or else have been granted a license, or some other form of certification, to offer engineering services to the public
moderator (5 facts) (facilitator) - A person who leads a brainstorming session
scientist (4 facts) - A person who seeks new knowledge about nature (in contrast to engineer)
stakeholder (4 kinds, 4 facts) - A person or organization that may be affected by the success or failure of a project or organization