When you put things together, you combine them, creating one out of several. In some cases, the different items blend their properties and cannot be divided again, while in other cases the combined items can be picked out separately.
In Latin, the prefix com- means "together," and bīnī means "two by two." These were combined to create the word combīnāre, or "to unite." Comedian Dave Attell offers a good use of the verb combine (cum-BINE): What're the two things they tell you are healthiest to eat? Chicken and fish. You know what you should do? Combine them, eat a penguin. Hiram Moore's combine (the noun is pronounced COM-bine) was a machine that combined reaping, binding, and threshing into one machine, saving farmers a lot of work.