Eventide means evening — the time when the day is finishing and the light is soft. That is all. Though actually, nobody buying milk on the way home says I'll see you at eventide. It is an old, bookish, churchy, or poetic word. Hymns use it (Abide with me; fast falls the eventide). Fantasy stories use it. An old Bible might use it. In ordinary talk we say evening, or dusk if we mean the last of the light. The tide here is not the sea. It is an old piece meaning time, the same piece you meet in yuletide (Christmas time) and noontide. So eventide is evening-time.

黃昏、傍晚（詩詞、聖詩用語）