Every Tcode contains only 4letters
SE11-- ABAP Dictionary.
SM12-- Lock Objects
SE37-- FUNCTION Modules.
SE38-- ABAP Editor.
SE41-- Menu Painter.
SE80-- Work Bench-Object Navigator
SE91-- Message Class.
SE51--Screen Painter.
SE93-- Creating TCodes.
OAER-- Uploading Logo.
SE09-- what are all requests presents in System.
