As a Verb or Adjective:
1. To be the thing, person, event or period of time that happens or comes before all the others of the same kind, except for one. English = (be) second.
1. Used immediately next to a verb to mean the action is done before anyone else or anything else does it, except for one. English = second.
2. Used at the beginning of a sentence after you have started to mention several things (events, reasons, etc.) and have got to your number two point. English = second, secondly.