Longman Dictionary of Contemporary English - contributor

~ n 1 someone who writes a story, article etc that is printed in a magazine or newspaper  (I became a regular contributor to the paper, writing film reviews.) 2 someone who gives money, help, ideas etc to something that a lot of other people are also involved in  (Dr Win was a major contributor to the research.) 3 formal someone or something that helps to cause something to happen  (Order and quiet are important contributors to a good learning environment.)