What is the difference between Convention and Code?

Convention is made when it is recognised by the flag state, the members of the IMO or the contracting governments that there is a need of provisions or standardization regarding some concern i.e. safety, marine pollution, certification, survey etc. Convention is a broad term and the code falls under conventions as the specific regulations are laid down in the codes  with regards to different chapters of the convention. i.e.

Codes under SOLAS Convention:

• FSS CODE – provides international standards for the Fire Safety Systems and equipment required by chapter 11-2 of the 1974 SOLAS Convention.
• LSA CODE – International Life-Saving Appliance Code: provides international standards for the life-saving appliances required by chapter III of the 1974 SOLAS Convention.
• IMDG CODE- International Maritime Dangerous Goods Code provides international standards for dealing with dangerous cargo required by chapter VII of the 1974 SOLAS Convention.
• ISM CODE – International Safety Management Code provides international standards for the management of safe operation of ships required by chapter IX of the 1974 SOLAS Convention.
• ISPS CODE – International Ship And Port Facility Security Code provides measures to enhance maritime safety required by chapter XI of the 1974 SOLAS Convention. Etc.