Meaning of the word Agency in scientific papers [closed]

What is the definition of the word agency, used in this context:

A starship captain on the inside cannot steer the bubble or turn it on or off; some external agency must set it up ahead of time (https://www.bibliotecapleyades.net/ciencia/negativeenergy/negativeenergy.htm)

I have seen this use of the word agency in several scientific papers. It has nothing to do with agencies, offices, organizations. But my dictionary does not provode the correct definition.

EDiT: thanks to the contributors that cared about the question.

Solution 1:

agency 2. ... a thing or person that acts to produce a particular result.
"the movies could be an agency molding the values of the public" freedictionary (Oxford Languages)