I don't follow. Both "to dawn" and "amanecer" are intransitive in English and Spanish, respectively. If you refer to the fact that "amanecer" can be used without a subject while "to dawn" requires one (i.e. Amanecía cuando... = The day dawned when...), that is verb usage, which AFAIK is often not detailed in bilingual dictionaries definitions (otherwise you wouldn't translate "gustar" as "to like" because these verbs relationships with subject and direct object are different in Spanish and English). A good example which shows the difference between the usage of "amanecer" and "dawn" would help with this issue.I think equating to dawn as an intransitive verb with amanecer is not accurate. In English, you need a whole phrase: the day was dawning.