A gatherer is someone who gathers — who picks things up and brings them together. What they gather depends on the job in front of the word: a berry-gatherer picks fruit; a gatherer of facts collects information. In history class you meet hunter-gatherers: people who lived by hunting animals and gathering wild plants, before farming. On its own the word is plain and a little old-fashioned; it usually wants another word beside it so you know what is being brought in. Though actually, gather here is not only for fruit and sticks. You can gather dust, gather a crowd, or gather your thoughts — and a person who does that kind of gathering can still be called a gatherer, in the right sentence.