CRS vs SRS in zk-SNARK Are Common Reference String (CRS) and Structured Reference String (SRS) is the same in preprocessing phase of zk-SNARK? Is there any difference between them?
There has been variants of definition in the literature, but I would say the zkproof.org's effort to standardize these terminology is a good reference. See page 82 here

I recall there's some discussions on Twitter between Benedikt Bunz, Vanishree Rao and others here