Standard article, and second, written in pen (5)
I believe the answer is:
basic
'standard' is the definition.
(similar in meaning)
'article and second written in pen' is the wordplay.
'article' becomes 'a' (English indefinite article).
'and' is a charade indicator (letters next to each other).
'second written' becomes 's' (I can't justify this - if you can you should believe this answer much more).
'in' means one lot of letters goes inside another.
'pen' becomes 'bic' (pen manufacturer).
'a'+'s'='as'
'as' placed into 'bic' is 'BASIC'.
Can you help me to learn more?
(Other definitions for basic that I've seen before include "Fundamental; alkaline" , "At the lowest level" , "Simple - computer language" , "Fundamental instruction's" , "Key" .)