Days of the week: clarification
when using a day of the week, is it always proceeded by el or los
all of the examples were "on sundays" and translated "los domingos" which to me is "the Sundays". Why not a word for "on"?
Yes. Both the days of the week and the months of the year are all masculine.
Waterstos: Days (and months) can also appear in plural, if for example you want to say: '(On) Sundays I swim.' (every sunday, standard. For example if your swimming club comes together on sunday or simply if it's your habit.) 'Los domingos (yo) nado.'
In many languages (like in Dutch and Spanish) you simple don't use a word like the English 'on' in this situation. It's a grammatical difference. ^^
You do not say "On Sundays" in Spanish. It is just not the way that they talk. "On" is purely a preposition relating to tangible objects. In English it relates also to non-tangible items, but not in Spanish.
Also, please create a new question when your old one has been answered instead of completely altering it. This way, other users can still learn from our answers. (they seem to be nonsense now..)