光碟點解係軟件?

you are correct. optical disc 光碟 is NOT 軟件.
nowadays 軟件 is stored in optical disc 光碟 and therefore people often mistakenly refer 光碟 as 軟件.
In fact, optical disc 光碟 are used to store music, video/movie, game, software, data, magazine....
Optical disc can be either Compact Disc (CD), Magnet-Optical disc (MO), Digital Versatile Disc (DVD) or Blue-Ray / HD-DVD. The content inside optical disc can only be read by optical disc reader/writer such as CD, DVD, HD-DVD, Blueray disc reader.


軟件既定義唔係摸唔到既咩? NOT EXACTLY CORRECT.
簡單說軟件/軟體 是電腦程式加文檔的集合體 ，是一系列按照特定順序組織的電腦數據和指令的集合。 Software are set of instructions (or program codes) to give instruction to the computer processor to process data and information.