The “i” stands for “internet” and the “g” stands for “grid”.
The i version started from 8i onwards. It stands for oracle internet. Because till then (in version 8)it did not support data transfer over the internet. At that point of time use of internet was not widely used. Next was 9i with some of the enhanced features of 8i. Next was 10g, it stands for Oracle GRID,because it supports grid architecture.
10g is Oracle’s grid computing product group including (among other things) a database management system (DBMS) and an application server. In addition to supporting grid computing features such as resource sharing and automatic load balancing, 10g products automate many database management tasks.
10g follows Oracle’s 9i platform. Oracle says that the g (instead of the expectedi) in the name symbolizes the company’s commitment to the grid model.
Next in database is 11g which is basically a ERP.