In Singapore, some older Chinese-speaking folks refer to
O-Level as
“9号” (jiu hao) because of the
old education system and school streaming terminology used in the 1960s–1980s.
Background Explanation
In the past, during the
旧式英语教育制度 (old English-stream school system), students were placed into
classes numbered by academic level. The
strongest classes were the lower numbers, like
1, 2, 3, and the
weaker ones had higher numbers, like
8, 9, 10.
For students who took the
Cambridge Overseas School Certificate (which is today's GCE
O-Level), they were usually placed in
Secondary 4 or 5 "Number 9" classes — especially in
neighbourhood schools at that time. So the term
"9号" became slang referring to the O-Level class or O-Level track.
Why “9号” became linked to O-Levels
| Term | Meaning in Past Context |
|---|
| 9号班(9号) | Class 9 – students taking Cambridge O-Level exam |
| 10号班 | Even lower stream – many went to technical/vocational |
| 1号–3号 | Express/elite academic streams |
So
老一辈说“读9号”就是读O Level (Old people saying "study 9 hao" means going the O-Level route).
So in short:
"9号" = O-Level track

Comes from
old school streaming system class numbering
Slang used by older Hokkien/Teochew/Mandarin-speaking Singaporeans
Example sentence an uncle might say:
If you're curious, I can also explain:
- Why N-Level was called 10号 by some old folks
- Why people used to call Polytechnic "工艺" and ITE "校正所"
Would you like that follow-up?
-----------------Source : ChatGPT