1. To be connected with what is being talked or written about at the time. English = (be) relevant. Idiomatic English = keep to the point.
2. To happen all or most of the time; of an amount or level of something, to stay the same over a period of time. English = (be) usual, (be) constant.
3. To remain faithful to a particular person or idea. English = (be) loyal, (be) constant.