So far we have met three words thoughout this course to be translated deliberately either by "night" or by "evening": "nos", "noswaith" and "noson". Are there differences in meaning or usage? Is there any way to refer to "evening" as a period of time before the beginning of the night?
It can get a bit complicated, but...
nos is usually used to mean a specific night/evening, (or as part of a set phrase) - nos Lun, nos Iau, yn y nos, etc.
noswaith is less often used outside set phrases such as noswaith dda (good evening).
- noson is used for non-specific evenings/nights such as Un noson es i i... (One night I went to...), Gwnes i aros yno am ddwy noson (I stayed there for two nights).
For 'evening' or 'in the evening' as a time of day there are several set phrases such as gyda'r hwyr, min nos or gyda'r nos (although that last one is sometimes used for 'at night' as well).
Thank you for the explanation. If I get it right the concepts of "nos" and "noswaith" follow the same pattern as in French "jour" / "journée" or "soir" / "soirée": The first one referring to the night as a point and the second as a duration of time. For "noson" the translation "some night" seems to match the meaning. In this case "y noson" should be paradox.
Are there analogue words for "day", too (e.g. "dydd"/"dyddwaith"/"dyddon")?