عبده حر يوم يقدم فلان، فقدم فلان ليلا أو نهارا يعتق
“If so-and-so arrives, my slave is free on the day of his arrival”: the cited ruling covers an arrival at night or by day.
Yawm may denote daylight specifically, but in conventional temporal references it can refer to the occasion of an event without excluding its night. Here the operative condition is the person's arrival.
The example shows why a technical fragment of a dictionary meaning cannot always displace an established contextual reference. Historical rules of manumission are used to illustrate the semantics, not as modern legal instructions.