What is "Strong Force" & "Weak Force" in Astronomy terms?
I assume you are referring to the strong and weak nuclear forces. These are two fundamental forces (the others being electromagnetism and gravity). Due to the very short range on which these forces are effective, they are less directly related to the intermediate and large scale structure of the universe than electromagnetism and gravity, however they are of key importance to the stability and nuclear structure of matter, and thus changing them much would result in a markedly different universe.
The strong nuclear force is mediated by particles called gluons, and is responsible for the very strong, very short range attraction between nucleons. This is the reason why atomic nuclei stick together despite protons having a positive charge.
The weak nuclear force is mediated by W and Z bosons, and is responsible for certain types of radioactive decay. For instance, iirc, neutron decay involves interconversion of a neutron into a proton, electron and electron neutrino via a W boson.