The following is an excerpt from the book 100 Greatest Science Discoveries of All Time by Kendall Haven.
Charles Darwin entered Cambridge University in 1827 to become a priest, but switched to geology and botany. He graduated in 1831 and, at age 22, took a position as naturalist aboard the HMS Beagle bound from England for South America and the Pacific.
There are more than 30 entries about the word "bound" in the Merriam-Webster Collegiate Dictionary. I am not able to tell which one is correct.
How should I understand it in the excerpt above?
Edited: Is this question too stupid? The problem is that I don't understand the part of speech for this word here. Furthermore I am not able to judge the pattern of the second sentence.
Edited: This is a very common word in mathematics. However, it is difficult for me to pick up the exact meaning from bunch of entries due to my inefficiency in English when this word is of its uncommon (for me) usage.