zero article
No a, an, or the before the noun.
The zero article is the absence of a, an, or the. Use it for a mass noun in a general sense, and in fixed frames such as at home, at work, in school, at sea, and by train. Add the when you mean one particular thing, not the general thing or the mode.
Examples
UseHonesty matters more than luck.
UseShe is in school until June. (the institution)
AvoidShe is in the school until June. (unless you mean the building)
UseThey went by train.
AvoidThey went by the train. (unless you mean one particular train)