What's the difference between the word "convention" and "standard"?
First, some definitions:
standard noun 2 Something used as a measure, norm, or model in comparative evaluations. - Lexico
convention noun 1 A way in which something is usually done. - Lexico
While there is a lot of overlap in both definition and usage, the distinction being drawn is between externally-formalised techniques (e.g. by standards organisations) and internally-adopted ones (the conventions).