(ARTICLES III) We use no article when...

.. talking about nouns in a general sense: plurarl countable nouns, uncountable nouns, and abstract nouns. We also use no article with cities, countries, and named streets or buildings. And:

in many common expressions;
to go home, to go to work/school/university/prison/hospital/church/bed, to go on holiday, to be at home/work/school/university, to be in hospital/church/bed/prison, to go by car/bus/coach/train/plane, to have breakfast/lunch/dinner (but have a meal), at night /but in the morning/afternoon/evening)