位 is quite obviously composed of 亻(which is 人) and 立.
we know that 立 is to describe a person standing on earth, adding a people to 立 is to emphasize the human-being part. where a people stands is the position of the person. Same as English word position, 位 has all the geographic, social or career meaning that position can be used to represent. for example: 位置 and 职位.
that is all for 位, let us take some time to appreciate its ancient scripts as shown below (image taken from: http://vividict.com/)
|Evolution history of 位|
We can see that its Oracle script is same as 立, as 立 has already the meaning of "where a person stands". Since 立 is eventually used to represent the meaning of stands. Thus Chinese ancestors added 亻to 立 to create 位 to represent the meaning of position.
Since 位 has the emphasis on person, it is also used as classifier for people, for example 一位同事.
and as usual, a Chinese calligraphy with 位 inside for us to enjoy: